This particular soundfont uses MP3 samples, so you will need libmpg123 to decode them: http://wiki.openmpt.org/Manual:_Samples#Loading_MP3_samples (for soundfonts this also applies if you are using Windows 7 or newer)

there is something else I discovered after I posted this bug. many samples .dls files that were already in ModPlug or added after this release now only play a "click" sound or all the sounds in the bank only play as a generic guitar sound and they were not like that before.

I'm not a clairvoyant, so upload the troublesome files or I cannot do anything about them.

I was going to say, "Are you sure you wanna down a 200mb dls file". but I opened up ModPlug alone with no modules they all worked like normal and sounded great. however, if I double click on this module to open it in ModPlug: http://www.mediafire.com/download/8d71y2nco4ampb4/macavity.it most .dls files start making glitchy clicks and guitars again.

It's pretty much impossible that opening a module would corrupt or change the registered DLS files. Anyway, original issue is solved => closed.