Microsoft OneCare Live

Firefox Portable will not connect to the internet if "Microsoft OneCare Live" is installed. As a matter of fact any application (I have only tested Thunderbird) will not connect to the internet. I have even tried to add the file manually to the firewall.
FYI I am using this setup on Vista.
If I turn off the firewall everything works fine. But I can't do that now can I :)

I know it is no fault of any other application than OneCare but I am just here in case if someone knows the solution. (Apart from not using OneCare)