Try to use rsro launcher or run it through RIbot, if that wont work i have no solution,
anyway there is many other reasons, if you use Win7/vista (still it should work) but you can try to set it run as another system like xp 98, run as administrator may help,
Most common solution would be, edit your pk file find server IP , and Edit your host file in
windows/system32/drivers/etc and there is host file,
Just few clues witch will help you alot if you will use search for farther actions