Just curious when you normally by software on line and download it from a web site do you not burn a back up copy to disk. It is your right and responsibility. LimeWire Pro can no longer be purchased on disk so there is no other option than creating you own disk. Anyway I do agree their should be some way of getting a copy of 4.8.1 from LimeWire but to my knowledge there is not. The only options you have is to either PM morfel at this link. Which I do not know will do any good.
https://www.gnutellaforums.com/members/mformel.html or pay for the current version of Pro.