The solution:
I was also with the same problem...
I found it: groups.google.com/group/tortoisegit-users/browse_thread/thread/ff1d81f59cd5fe90
Follow Frank's suggestion in the link above; install http://msysgit.googlecode.com/files/Git-1.7.0.2-preview20100309.exe instead of msysgit and be happy :)