From a Mambo.com invite email:

http://www.mambo.com/templates/xpress_01/
xpress_01.jsp?accessCode=1448.141338.XXXXX
If the link above appears to be inactive, copy and paste it into the browser's location bar and hit Enter. Please note: This link may wrap to multiple lines.

Um, Mambo, wouldn't it simplify things for everyone if you just placed xpress_01.jsp in your root directory, changed the name to something shorter, like x1.jsp and changed the name of the accessCode variable to something like, "ac"? Then the URL would contain the same information but only be something like 48 characters long, instead of 83, thus making wrapping in email highly unlikely. (Sorry for you non-web-programmers, but things just don't have to be this complicated!)