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It was reported that entering the user name without "@me.com" resolves this issues. (see comments below)
Hello, "%" and ";" are actually in the row of additional keys, but you need to scroll the row horizontally to get to them.
So, entering the username without @me.com solved the http status 402 problem for you?
Also on Wikipedia: "As an example of its use, however, Apple's MobileMe service generates a 402 error ("httpStatusCode:402" in the Mac OS X Console log) if the MobileMe account is delinquent." http://en.wikipedia.org/wiki/List_of_HTTP_status_codes#402
Hello, according to the list of HTTP Status Codes, code 402 means "Payment Required". See http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html

I'm not sure why that is returned. Can you connect to your iDisk on your Mac? Are you absolutely sure you're using the correct login details?