Error: “Workspace or data source is read only.” from file geodatabases

After updating from ArcObjects 10.0 to 10.1 (service pack 1), we are receiving this error quite often:
“Workspace or data source is read only.”

• Our ArcObjects applications update and alter featureclasses and tables in file geodatabases.
• These applications have been doing exactly the same things in 10.0 without any problems.

This is really a BIG issue, if there is no solution, we’ll have do downgrade and prevent our customers from upgrading to 10.1.