Open Source Document Management System | OpenKM

i am enable to undo check out the document . after check in,i logged in as okmadmin and i did cancel checkout then exception is coming like document is loked.
i dont know what happened,can u help me out.

or

can u tell me how to delete locked document from db.

Which OpenKM version are you using ?
Can you post here the error that might appears in server.log ( only the stack trace error ! )