In my case I knew there was a serious problem with the version based on process of elimination. If Windows Media player and other players worked, then it was iTunes. If other streaming internet radio programs played ok, then it was iTunes. I maintain several players and internet radio applications so a comparison was very easy for me.
I uninstalled and reinstalled twice after doing a complete clean of all vestiges of the program from various locations and folders.
Basically all you need do is run the standard uninstaller. Then use the Windows search feature to locate any remaining pieces under the search phrase "iTunes". You need to be sure to remove the iTunes library file (has an .itl suffix) because the one installed with 10.5 will not talk to 10.4. I tried and it gave repeated errors and iTunes 10.4 would not launch for me.
There are other threads here offering a step by step. Some suggest uninstalling Bonjour as well but I didn't find that necessary.
The back version of 10.4 was available at www.filehippo.com
I also await the fix but I suspect that holding them to a specific date and time will be heart breaking.
If you don't want to downgrade or if the process is too technical, try installing a different player for the interim such as FooBar2000, XmPlayer, or the Spider Player. For Net Radio I like RadioSure or Tapin. Those will get you by.