Access user account permissions

Hi,

I have a database I would like to convert between Access
versions, "secured" via an .mdw workgroup file.
Unfortunately, I keep getting a "the current user does not
have permission to convert or enable this database"
message when opening the database (via the .mdw) in a
later version of Access in order to convert it.

Any idea what I need to do to make sure the user has
enough permissions to do this (I checked the list in User
Permissions and everything is ticked), or is this a known
issue with Access?

Any help/information gratefully recieved