How to view Eagle gerber files in ViewMate?
I have run into this exact problem myself. The issue is that Eagle is playing a bit "fast and loose" with the formatting of the drill coordinates, and this causes Viewmate to infer the incorrect scaling. I messed around for a while before I finally wrote a short Perl script that reads in the Eagle file and writes a fresh one with a fixed number of digits for the coordinate values, which Viewmate reads correctly.

Unfortunately, that script is on a different machine, and it will be several days before I have access to that machine again. When I do, I'll add the script here. In the meantime, maybe this is enough of a clue to get you unstuck.