Fixed error in main script when using other database engine. Fixed #1166.
Fix list_of_speaker overlay

* Issue a warning message, if a overlay raises a exception
* Fixed #1131
Merge pull request #1165 from ostcar/list_of_speaker_overlay

Fix list_of_speaker overlay
Merge pull request #1167 from normanjaeckel/MainError

Fixed error in main script when using other database engine. Fixed #1166.