I use the forum to post a problem ad the solution, hoping it may be usuful to other users.

PROBLEM:
Running LimeSurvey I get this message:

Internal Server Error
The table "{{settings_global}}" for active record class "SettingGlobal" cannot be found in the database.
An internal error occurred while the Web server was processing your request. Please contact the webmaster to report this problem.

SOLUTION:
The problem is NOT caused by LimeSurvey (I havent't changed anything in the last days), but the disk on the server was almost full, so the services aren't able to run.
By manually checking and deleting old files (in my case old backups generated via the cron command) Limesurvey automatically started up.

CONSIDER TO CHECK AND DELETE:
- backups
- logs

P.S. My system is running on a Linux system (Ubuntu 12), LS is updated to Version 2.05+ Build 150413, but this is not relevant for the problem