An update about this Bug.
If i create a new ticket connected to a custom field in I-doit I get the following error.
PHP Warning: Invalid argument supplied for foreach() in /usr/share/i-doit/src/classes/cmdb/dao/isys_cmdb_dao.class.php on line 112
This error is repeated for every custom field that is filled in for the ticket. (So if i create a ticket with 3 custom field entries, give the php command to put the tickets in I-doit, I get this error 3 times beneath eachother!)