few tcodes loggs off my sap in vista ( sapgui 6.4 version)

hi evry ,

im using windows vista and SAP GUI 6,4 with patch 23 .. but still some transactions does not run . like V/06 .. when ever i use that transaction code ..or even follow the path and open ,,,it will shut down my sap.....i checked with my team member who is using windows Xp and it was running fine for the same server ..

please some one help me regarding this ...let me know if any know any patch for 6.4 version ( i cant install 7.1 now as i dont have access to service market)

thanks

madhan

rewards for sure