In 2007 there were 2 Pro options - Pro (6 months of free updates & support) and Extended Pro (12 months of free updates & support). Extended Pro wasn't introduced until August 2007.

So if you bought Pro before August, you can't download a new Pro installer for free. If you bought after August, you need to have bought Pro from the official site (payment appears on your credit card to LimeWireLLC): Lime Wire » Download LimeWire

If you bought plain old Pro, even from the official site, your email address won't be in the database any more.
If you bought Pro from a different (scam) site, your email address was never in the database.

The official site tells you that your Pro payment is a one time payment. What it doesn't tell you is that your one time payment entitles you to free updates only while your Pro benefits are current...that means if you bought 6 months worth of Pro, you can only download free updates for 6 months. Likewise for Extended Pro (12 months). And it's up to the user to save & back up Pro installers...if you lose your old version of Pro then you can't download a free older installer. Even if you paid the official site for it.

That's something that LW need to make clear to their customers. They've been asked to do it, but they haven't. They probably never will