What format are they in? Have you tried the free Media Player Home Cinema instead?
I have a TiVo and needed a good way to play my recordings in different formats.
I did a Google search for TiVo conversion and hit several links. I like to try before I buy because I have been burned in the past. I have tried at least 7 other products. Only pavtube worked great for all my files including TiVo. I have upgraded from vista32 to win7 and have no problems running pavtube. It's perfect.