If it's your personal download page...you'll be able to download Pro again.
How long ago did you pay? Remember that Pro updates & support are good for 6 months (or slightly longer sometimes), so if it's been more than say, 7 months...your email address might not be in the database any more.

Sometimes there's a glitch, as in valid email addresses not being recognised within the 6 month period. If you did pay less than 6 months ago, check the thread below & send a PM to limenathan. He should be able to help you
Problems getting your LimeWire Pro after payment or other Pro payment issues etc