DP 8.00 IDB backup error

I get this error whenever i try to backup idb:

[Normal] From: OB2BAR_POSTGRES_BAR@XXX "DPIDB" Time: 5/26/2015 10:36:35 AM

Check of the Internal Database consistency succeeded

[Critical] From: OB2BAR_POSTGRES_BAR@XXX "DPIDB" Time: 5/26/2015 10:36:35 AM
An error occurred during file search

I checked the database with "omnidbcheck -extended" and everything is fine. Also, i restarted dp services.