You're better off switching to UO Cartographer, since UOAM is no longer supported by its owner (and works with both clients, unlike UOAM).
Any existing .map files for UOAM will work for UO Cartographer, if you transfer the files into the UO Cartographer's folder. For example, the Treasure Hunter T-map files were not available in the UOAM download packages for several years prior to its abandonment due to some error on their end, but the file can be gotten by creating or copying a .map file and posting the data in the Fishing & T-hunting forum sticky post that provides that data.