I haven't found any section in these forums to do with upgrading between versions of LimeWire Pro!

I have version 4.9.11 which I purchased from:

Merchant: LimeWire PRO
Order ID: VZYC0B34F337
Order Placed: Saturday, August 6, 2005 12:57:06 PM PDT Amount of Transaction: $18.88 Payment Type: Visa

I have visited the download page and put in my old email address which I had used when I purchased this software. On clicking 'submit' the error returned was that this email address was an invalid one.

So how do I upgrade to version 5?