I think you're trying to use XM on a Sirius cab. Although the companies have "merged" I don't believe those app's are working for each other. There's a thread in the software forum for C-Apisro and towards the end of it, you'll find some links for XM app's for listening in your ppc.
Here's the link to XDA for the app, Rawintellect found it and posted it... hit 'em up for a thanks, they're much appreciated by us all!!
http://forum.xda-developers.com/showthread.php?t=450259