So, you don't have any new entry under par2 tab?
Exit alt.binz
Delete par2info.abz and par2.exe from the misc dir (for the location of the misc dir - consult FAQ)
Start alt.binz
Note if par2.exe has appeared in misc dir (it should)
Try to download something.
If all that doesn't help, please take screenshots of the relevant par2/unrar panels in setup