Ok, try this: When the dialog box pops up, just drag it down the page a bit (don't click anything within the box) & then click on the option to download the offline installer.


Once you click on that option, you should see the file within the dialog box change to 'LimeWireWin-Full.exe'. See if it works then. If you're still having no joy, try using the 'other' installer.
Installing using the 'other' installer

If you paid for a year's worth of Pro last year, you didn't get it from the official site. They've just introduced a 1 year deal recently. So no...you won't be able to download Pro from the official site without paying again.