EPDM error " could not access the item in the database" to attempt check in file.

Checking Google here are a couple of clues. I would say check your log as described by Javelin and see if it give you any additional info. Unfortunately with so little to go on it could be anything.

http://www.javelin-tech.com/blog/2014/06/epdm-access-item-database/#.WMagDG8rLmE

"Could not access the item in the database" when trying to destroy deleted items

What is going on!? "Could not access Item in the Database" | MySolidWorks