It seems from the TntMPD forum that they were having more and more of a difficult time tailoring TntMPD to Wine (which really they should never have had to) so at version 2.0.57 they removed the pieces that made TntMPD compatible with Wine.
The beginning issue with the newer versions is that Jet 4.0 will not install properly into CrossOver. The other prerequisites all install well with CrossOver with a bit of tweaking (move to a win98 bottle, add the requirements, move back to a winXP bottle).
Unfortunately at this time we don't plan to expand support for this and being that the application broke on the TntMPD side means that it's not something we can fix on our side. Truthfully all that you can do at this time is wait for CrossOver to become more advanced or wait for the tools that TntMPD uses to change.
I plan to peruse the beta side a bit with TntMPD and poke around but I make zero promises.
I wish it were better news, but being a small company means that we have to focus on more widely used programs and getting the functionality within them up.
My apologies.