Add to google calendar not working in Firefox 4.0?

Tried to add a couple of things to my Google calendar recently. It used to work but now I get this message:

The page isn't redirecting properly

Firefox has detected that the server is redirecting the request for this address in a way that will never complete.

This problem can sometimes be caused by disabling or refusing to accept
cookies.

Using Firefox 4.0. Something I did? Anyone else having this issue?

Actually tried it with IE 8 and it worked fine so it must be Firefox related.