We have had a lot of complaints about the new media player and it's lack of support for certain files. We do not have the code to fix the old media player, so a lot of problem were being worked around instead. The media player was also the only remaining part of shareaza that was not open source. The media player was rebuilt from scratch to allow us to actually fix what was wrong with it and we also made it more secure. In the process of doing so there were some regressions as far a support for certain files. We understand your frustrations and we are working hard to resolve them.
For those of you who do not wish to wait until the new media player is up-to-par, I have created a simple installer to replace the media player in shareaza 2.5.1.0 with the old player from 2.4.1.0. Visualizations still will not work, but you should be able to play all the files you could before.
>>> Download Legacy Media Player Installer <<<