Dualbooting Win7 and SL

[Giuly]

Hi,
I have now SL running. I installed it on a HDD (MBR-Partitioned) where Win7 is installed. When I try to boot Win7 now, I get Error 0xc000000a (Error while Startchoose, Access on an neccessary device not possible).

only thing I did is installing chameleon, before that, it worked.

Is there anything I can do to fix that?

Regards