My invitee to Skydrive Group cannot see Groups on his menu

I have invited a new member to my skydrive group.

I usually tell new members to set up a microsoft log in, then log in at skydrive.live.com, click on "Groups" on the left and then click "View Group Invitations" at the top. My invitee has set up an account successfully; however he does not have the Groups item on his left hand menu. I have never come across this before.

I tried asking him to click on the link in the email invitation instead. (As this process can be a bit flakey, I normally ask invitees to follow the procedure above instead).

However when he clicks on the link, it says "processing error, try again later."

Any idea why he might not have Groups in his menu?