In any case I got the same exact *s of norm3777 since I upgraded to Vista AND upgraded to 5.7.9.0 - don't know which upgrade actually caused it. Srtange as I have turned off firewall and Internet connection is fine - please HELP.
I had exactly the same problem. The only way I found to solve it was to uninstall and reinstall completely XMM. I had an XMM installation folder that was not under "My Documents" (XMM db was there though).
It seems that this is the only visible change since my reinstallation. Now XMM Places all its files under "My Document". I guess through incremental upgrades since the 1st 5.x release the move of all files there was never done and when it became really mandatory, the update was failing.
So try to move your files or reinstall and let me know.