I am moving entries from a subproject to the rootproject more then one time. After the last move i have following error:
SYSTEM WARNING: 'Invalid argument supplied for foreach()' in '/homepages/45/XXXXXXX/htdocs/mantis/core/columns_api.php' line 363
This error is showing at least 9 times in overview and list.
All other projects are correct. 
At first i checked the database for damaged entries. I think it´s ok. The entries are moved to the new project. I found few entries in FILTER with project_id -1 to -5... Deleting this has no effect.
Now i hope for your help...
Thanks.
Crosspost to the german forum viewtopic.php?f=9&t=23716
SOLUTION:
After laborious debugging (my Delphi can it better
) was pretty clear what he looks for the mantis_config_table [/ b]. There was entries for this project with names of columns available. Those were the only entries with such content. After removing the entries everything is back to normal.
Maybe someone with internal information can explain that ...