XML file open error
A -6013 error is a file open failure.
There are two possibilities:
1) Files were created by one user, and a second user does not have sufficient permissions for those files.
2) one or more of the files in the WorkDir became corrupt, possibly during a system or application crash.
Solution
1) Check file permissions for the user in question, read/write is required.
2) Unless you are using consumption tokens, it is always safe to delete the WorkDir and its contents (they will be re-created during app startup). If you are using consumption tokens, delete all files in the WorkDir except the license file.