I did exactly what you said. Here's my code:
http://www.nittanyfootball.com/ubbthreads/dosearch.php?Cat=0&Forum=All_Forums&Name=$player_firstname%20$player_lastname&Searchpage=0&Limit=25&&fromsearch=1&fromprof=1
The Name variable is replaced with the name of the player in the roster. I'm not sure what this is searching though because I just get a screen back that says No Matches. When I do a search for the same name in the regular search function it works fine.
Even using the URL string that you said to copy it looks like it's using the search function. Is that correct? I thought that the Name variable had to be the ID of a registered user on the board. That's not what I want. I want the names of players in posts and titles to be searched and displayed.