diff --git a/admin/inc/class.admin_cmd.inc.php b/admin/inc/class.admin_cmd.inc.php
index a1b4a1fc00..aeaaa5fab0 100644
--- a/admin/inc/class.admin_cmd.inc.php
+++ b/admin/inc/class.admin_cmd.inc.php
@@ -160,7 +160,7 @@ abstract class admin_cmd
 	 *
 	 * @return string
 	 */
-	function __tostring()
+	function __toString()
 	{
 		return $this->type;
 	}
@@ -274,7 +274,7 @@ abstract class admin_cmd
 	 * of the command (to not allow to send new commands with an earsdroped secret) and the md5 hash
 	 * of the md5 hash of the config password and the install_id (egw_admin_remote.remote_hash)
 	 *
-	 * @return string sussess message
+	 * @return string success message
 	 * @throws Exception(lang('Invalid remote id or name "%1"!',$this->remote_id),997) or other Exceptions reported from remote
 	 */
 	protected function remote_exec()
@@ -380,35 +380,42 @@ abstract class admin_cmd
 			$vars['type'] = substr($this->type, 11);
 		}
 
-		admin_cmd::$sql->init($vars);
-		if (admin_cmd::$sql->save() != 0)
+		try
 		{
-			return false;
-		}
-		if (!$this->id)
-		{
-			$this->id = admin_cmd::$sql->data['id'];
-			// if the cmd has no uid yet, we create one from our id and the install-id of this eGW instance
-			if (!$this->uid)
+			admin_cmd::$sql->init($vars);
+			if (admin_cmd::$sql->save() != 0)
 			{
-				$this->uid = $this->id.'-'.$GLOBALS['egw_info']['server']['install_id'];
-				admin_cmd::$sql->save(array('uid' => $this->uid));
+				return false;
+			}
+			if (!$this->id)
+			{
+				$this->id = admin_cmd::$sql->data['id'];
+				// if the cmd has no uid yet, we create one from our id and the install-id of this eGW instance
+				if (!$this->uid)
+				{
+					$this->uid = $this->id . '-' . $GLOBALS['egw_info']['server']['install_id'];
+					admin_cmd::$sql->save(array('uid' => $this->uid));
+				}
+			}
+			// install an async job, if we saved a scheduled job
+			if ($this->status == admin_cmd::scheduled && empty($this->rrule))
+			{
+				admin_cmd::_set_async_job();
+			}
+			// schedule periodic execution, if we have a rrule
+			elseif (!empty($this->rrule) && $this->status != admin_cmd::deleted)
+			{
+				$this->set_periodic_job();
+			}
+			// existing object with no rrule, cancel evtl. running periodic job
+			elseif ($vars['id'])
+			{
+				$this->cancel_periodic_job();
 			}
 		}
-		// install an async job, if we saved a scheduled job
-		if ($this->status == admin_cmd::scheduled && empty($this->rrule))
-		{
-			admin_cmd::_set_async_job();
-		}
-		// schedule periodic execution, if we have an rrule
-		elseif (!empty($this->rrule) && $this->status != admin_cmd::deleted)
-		{
-			$this->set_periodic_job();
-		}
-		// existing object with no rrule, cancle evtl. running periodic job
-		elseif($vars['id'])
-		{
-			$this->cancel_periodic_job();
+		catch (Api\Db\Exception $e) {
+			_egw_log_exception($e);
+			return false;
 		}
 		return true;
 	}
@@ -461,7 +468,7 @@ abstract class admin_cmd
 	}
 
 	/**
-	 * Instanciated the object / subclass using the given data
+	 * Instantiate the object / subclass using the given data
 	 *
 	 * @static
 	 * @param array $data
diff --git a/api/src/Vfs.php b/api/src/Vfs.php
index 86cf7e145f..767bdfe3c8 100644
--- a/api/src/Vfs.php
+++ b/api/src/Vfs.php
@@ -69,7 +69,7 @@ use HTTP_WebDAV_Server;
  */
 class Vfs extends Vfs\Base
 {
-	const PREFIX = Vfs\StreamWrapper::PREFIX;
+	const PREFIX = 'vfs://default'; // using the original definition sometimes gives an autoloading error: Vfs\StreamWrapper::PREFIX;
 
 	/**
 	 * Name of the lock table
diff --git a/setup/inc/class.setup_cmd_header.inc.php b/setup/inc/class.setup_cmd_header.inc.php
index 6d8015f5d4..67e430004d 100644
--- a/setup/inc/class.setup_cmd_header.inc.php
+++ b/setup/inc/class.setup_cmd_header.inc.php
@@ -313,7 +313,7 @@ class setup_cmd_header extends setup_cmd
 	 *
 	 * @param string $arg current cli argument processed
 	 * @param string $name name of the property
-	 * @param array/string $data string with type or array containing values for type, allowed
+	 * @param array|string $data string with type or array containing values for type, allowed
 	 * @param mixed $value value to set
 	 */
 	private function _parse_value($arg,$name,$data,$value)
@@ -321,7 +321,7 @@ class setup_cmd_header extends setup_cmd
 		static $domain=null;
 
 		if (!is_array($data)) $data = array('type' => $data);
-		$type = $data['type'];
+		$type = $data['type'] ?? '';
 
 		if (isset($data['allowed']))
 		{
@@ -341,31 +341,37 @@ class setup_cmd_header extends setup_cmd
 		}
 		elseif ($value !== '')
 		{
-			self::_set_value($GLOBALS,str_replace('@',$domain,$type),$name,$value);
+			self::_set_global(str_replace('@', $domain, $type), $name, $value);
 			if ($type == 'egw_info/server/server_root')
 			{
-				self::_set_value($GLOBALS,'egw_info/server/include_root',$name,$value);
+				self::_set_global('egw_info/server/include_root', $name, $value);
 			}
 		}
 	}
 
 	/**
-	 * Set a value in the given array $arr with (multidimensional) key $index[/$name]
+	 * Set a value in $GLOBALS with (multidimensional) key $index[/$name]
 	 *
-	 * @param array &$arr
 	 * @param string $index multidimensional index written with / as separator, eg. egw_info/server/
 	 * @param string $name additional index to use if $index end with a slash
 	 * @param mixed $value value to set
 	 */
-	static private function _set_value(&$arr,$index,$name,$value)
+	private static function _set_global($index, $name, $value)
 	{
 		if (substr($index,-1) == '/') $index .= $name;
 
-		$var =& $arr;
-		foreach(explode('/',$index) as $name)
+		$var = null;
+		foreach(explode('/',$index) as $n)
 		{
-			$var =& $var[$name];
+			if (isset($var))
+			{
+				$var =& $var[$n];
+			}
+			else
+			{
+				$var =& $GLOBALS[$n];
+			}
 		}
-		if (true) $var = $value;
+		$var = $value;
 	}
-}
+}
\ No newline at end of file
diff --git a/setup/inc/class.setup_cmd_install.inc.php b/setup/inc/class.setup_cmd_install.inc.php
index f61c54b1f8..3392726319 100644
--- a/setup/inc/class.setup_cmd_install.inc.php
+++ b/setup/inc/class.setup_cmd_install.inc.php
@@ -109,8 +109,8 @@ class setup_cmd_install extends setup_cmd
 		$setup_info = self::$egw_setup->detection->upgrade_exclude($setup_info);
 
 		// Set the DB's client charset if a system-charset is set
-		self::$egw_setup->system_charset = strtolower($this->charset);
-		self::$egw_setup->db->Link_ID->SetCharSet($this->charset);
+		self::$egw_setup->system_charset = 'utf-8';
+		self::$egw_setup->db->Link_ID->SetCharSet(self::$egw_setup->db->Type === 'mysql' ? 'utf8' : 'utf-8');
 		$_POST['ConfigLang'] = $this->lang;
 
 		if ($this->verbose) echo lang('Installation started, this might take a few minutes ...')."\n";
@@ -120,4 +120,4 @@ class setup_cmd_install extends setup_cmd
 
 		return lang('Installation finished');
 	}
-}
+}
\ No newline at end of file
diff --git a/setup/inc/functions.inc.php b/setup/inc/functions.inc.php
index 9e8d69c45f..0a5f1a16f3 100644
--- a/setup/inc/functions.inc.php
+++ b/setup/inc/functions.inc.php
@@ -30,7 +30,7 @@ if(file_exists(__DIR__.'/../../header.inc.php'))
 	include_once(__DIR__.'/../../header.inc.php');
 }
 // for an old header we need to setup a reference for the domains
-if (!is_array($GLOBALS['egw_domain'])) $GLOBALS['egw_domain'] =& $GLOBALS['phpgw_domain'];
+if (!isset($GLOBALS['egw_domain']) && isset($GLOBALS['phpgw_domain'])) $GLOBALS['egw_domain'] =& $GLOBALS['phpgw_domain'];
 
 /*  If we included the header.inc.php, but it is somehow broken, cover ourselves... */
 if(!defined('EGW_SERVER_ROOT') && !defined('EGW_INCLUDE_ROOT'))
@@ -88,4 +88,4 @@ if (!function_exists('version_compare') || version_compare(PHP_VERSION,$GLOBALS[
 	echo "EGroupware now requires PHP {$GLOBALS['egw_setup']->required_php_version} or greater.\nYour PHP version is: ".PHP_VERSION."\n";
 	echo 'Please contact your System Administrator.';
 	exit;
-}
+}
\ No newline at end of file