You're probably right. I would guess that the location of the 'xxxx_covers' folder is hard-coded. The folder loaction is not available among the OCD preferences, and there doesn't seem to be any registry setting for it either.

But what's the name of you database file?

As Bob pointed out, if you have a database file called 'myCDcollection', the external cover files will be stored in a subfolder called 'myCDcollection_covers'. OCD will create an 8 character file name with a jpg extension for each cover, like