I just started getting a prompt stating that the plug-in needed to read my MP3 files is not registered, and that I can register by clicking the Register Buttion. But when I try to do that I get a prompt that tells me that an error ocurred while trying to open one or more files. The requested plug-in does not have the necessry features unlocked.

First off, why I am getting this now? I never had this problem before. And why can't I register? Any help is appreciated.