Without knowing anything about your situation, its tough to formulate assistance. there is no such animal as a "Palm pre plus 2". There is a "palm Pre Plus" and a "Pre 2".
Maybe you mean a North american carrier "Palm pre plus" model that's running WebOS 2.1 - that could be referred to as a "Franken Pre Plus 2" ... that's way out there i know, but just maybe thats what you mean????
Without more detailed info and specifics its hard to offer assistance.
I can suggest making sure all other tethering programs be uninstalled before attempting to install freetether.
good luck, hope you and your friend find the problem.