Strange colors on PowerMac Machine OsX

Strange colors on PowerMac Machine OsX
if it used VmWare or Std i have strange color palette as result.
I had benn made a grab of screen here 

http://i1249.photobucket.com/albums/hh511/tlosm/qyellow_zps1d2dfc18.jpg

My Machine is a PowerMac G5 Quad with Nvidia 7800Gtx 512mb

thankyou
Luigi