Vista - Issue with WMC and AverTV Hybrid VolarMax USB

I recently purchased an AverTV Volar Max USB tuner for my HP dv5z and have noted an issue with Windows Media Center (WMC). When I connect an analog cable tv signal (no set top box) I get lots of dropped frames and general screen flicker. Basically, it is unwatchable. WMC is fine with my over the air digital antenna however. Has anyone else had this problem? Are there any WMC patches to download/install? I am running Home Premium 64bit with SP1 and all updates installed as of today.

As an aside the same set-up in the AverTV software gives me smooth video on the analog source, so I don't think that the setup is the source. Just something in how WMC is decoding or something.

I would really like to use WMC since the guide is leaps and bounds better than the AverTV software.

Any help is appreciated.