GameDevChris - That was indeed the problem. In the winsetup file, I had pressed the downgrade to 16-bit option. (My graphics card was having issues with the resolution, so I had played around with the winsetup file to get it to run; turns out all I actually needed to do was turn off the graphics filter, not downgrade to 16-bit.)
The dial works fine now. Thanks!
The dial works fine now. Thanks!