Hi and welcome...
Did you install your new Pro version as an upgrade
over an existing install of LimeWire ?
And, not exactly sure what you mean when you say that your downloaded files do not "show up in the library..."
To maybe help you with a fix right now (I am taking a guess about your upgrading) click on >
If you've updated LW and can't find your downloads!
which you will find in my signature below...
btw, Do you know an Uncle Compoop ? 
Sorry. Couldn't resist it !