Yeah, I'm having trouble too.   When I loaded Gal Civ II it said there was an udate, but I'd have to restart the game to get it.   So I restarted and nothing happened.   Still version 2.02.007.   What is the current version and how would I update if there is a newer one than what I have?

I have solved the problem.

I removed impulse and downloaded it again from their webpage.  When attempting to install it, the installation failed because I did not have internet explorer 7.0 or better. 

I am a mozilla user.

So I belive this was the cause of the error.

I am having the exact same problem as the OP.   I do have IE 7 as well as Net 2.0.    I keep getting the same message that Impulse needs to update and it gets stuck at 88.9% and attempts to retry the update.    Any help would be appreciated.

Edit.. Uninstalled Impulse and downloaded it new.  After reinstalling it was able to fully update.   This worked for me so hopefully it will work for others.    Its a pain in the butt I know but at least it solves the problem.