According to Microsoft:

"Nimo and Tsunami codec packs are untested compilations of various codecs and filters commonly used on the Internet."

"Incompatibilities are known to exist with some of the components in the packs."

"The incompatibilities can cause serious playback issues in Windows Media Player and other multimedia programs, lead to system corruption, and make it difficult for Microsoft Support to diagnose and troubleshoot playback issues."

http://www.microsoft.com/windows/windowsmedia/software/v7/v7faq.aspx?section=CODECS&qu...S1#NAME_CODECS

Jerry Jones
http://www.jonesgroup.net