Thx everybody for testing it.
HERE is a new, fixed version for you.
Slin helped me alot with testing, thank you Slin.
The new version should run on all ShaderModel3.0 cards. The gpu+weld on cpu mode should also be way faster now, so please give it a try again and post your results.

Thx
ChrisB

my numbers:
cpu: 24.5sec
gpu: 13.5sec
gpu+weld: 16.5sec

PC:
PentiumD 820 (2*2.8Ghz)
Geforce 6600GT
1GB ram