Reg Complete Link Broken when Registering from a Pop-Up AdWords Page

1. Go to an AdWord Page such as https://www.curriki.org/xwiki/bin/view/AdWordsJump/SearchEmailJoin1209Math?xpage=popup

2. Fill it in and submit

3. Go to mail and look at URL.

Bug
Has extra characters that need to be removed.

Notice the ?xpage=popup? - It is taking the URL from the adwords page.
http://www.curriki.org/xwiki/bin/view/Registration/Complete?xpage=popup?xwikiname=testingtodd9&validkey=Z8YRMEVJBai0gZyT

Here is an example of a correct URL.
http://www.curriki.org/xwiki/bin/view/Registration/Complete?xwikiname=testingtodd5&validkey=6NuYrJndk0nhpQoa