Rogean doesn't believe in P99 players having friends apparently
[You must be logged in to view images. Log in or Register.]
Sorry, sounds like your out of luck. You might want to try a multi-file text search (eg. using the command-line grep tool, if you're on Linux/Mac) to look for one of your friend's names, to see if maybe they're still present in some other file (those files aren't in any special computer code or anything; a friends list entry in them is just "Friend0=*NULL*").
But if not, it seems they're truly lost, as the server has no awareness of friends lists whatsoever (that I know of): they're purely kept client-side.