I have a mac laptop. I was told to download classic limewire since I have Mac OS 10.4? I paid for limewire classic pro. Once I go through all the steps, its says, "there is nothing to download"

For OSX 10.4 you need LW 4.18. Pro download page (click 'Classic' link on left side of page) (click 'this' link to see image), if you don't have it already.

You will receive that error message if you had a later version of LW installed at any stage. Go to your OSX -> Library -> Receipts folder & arrange it by list view, scroll down to i, find install limewire.pkg & move it to the trash. Sample image Receipts folder sample image. Then you can try installing LW 4 again.