5
down vote
accepted
Check to see what format is being used for the database. it's possible that it's using a Jet 3.5 database, which is no longer supported, and cannot be opened directly: (source)
VB6 only supports Access 97 straight out of the box, and has to have service packs applied to support newer versions: (source)
After a little more research, Access 2013 supports Access 2000 and later versions through Access 2010, and requires databases made in earlier versions to be converted using an earlier version of Access (source)