Installing a 9800 Radeon ATI Video Card in a G5

[beno]

I have a G5 - Power PC, with a 2GB Dual Processor, running OS 10.4.11

I'd like to install a 9800 Radeon ATI Video Card.

The vendor says it's compatible but my attempts have been unsuccessful.

Here's a link to the product:
http://cgi.ebay.com/NEW-Mac-ATI-Rad...o_TV_Cards?hash=item4837953a1b#ht_4671wt_1101

Any advice?
Is it incompatible?

Thanks in advance!