At a first guess, I would think it has less to do with the embedded font, and more to do with the encoding of the CSS.
While the ePub 2 spec wasn't explicit on it, the CSS should be UTF8 encoded, but the whether or not the byte order marks are there shouldn't matter. So my guess is that there is something in the tool chain you are using that is outputting UTF8 that is causing RMSDK problems.
Have you tried editing CSS with non embedded fonts?
Last edited by Jim Lester; 06-09-2011 at 03:28 PM.
Reason: Correctness :)