The problem is with the VSD use of jpg images for the mouseover.
Easiest solution is to make the image the way you want it and save it as a jpg.

Here's the image on your server which is causing the problem:
http://www.jsminiatures.co.uk/staging/files/mo_about_btn_reg.jpg

Thanks Dave. Got it now.

Buttons are looking good now on your test site :-)

Thanks for letting us know you're sorted