I am not sure about the specifics of your application hardware/OS, however, the DOS Mounter demo currently on the website is an older version than what they are currently shipping. I downloaded it (DOS Mounter 98) and found that it did not work "perfectly", however, when the purchased disk arrived (version 3), it worked without any problems. I did have to go and manually trash the demo version from my hard drive to eliminate the demo problems.
Tom DeRousie
http://www.modernimaging.com