i still get the invalid parameters, this is how it looks after i have changed everything.

Code:
 on *:text:@[JP]Rina-Uchiyama:#abcd:{ 
  var %num = $rand(1,$findfile(C:\Documents and Settings\FaBiAn\My Documents\My Pictures\Rina Uchiyama,*.*,0)) 
  var %file = $+(",$findfile(C:\Documents and Settings\FaBiAn\My Documents\My Pictures\Rina Uchiyama,*.*,%num),") 
  dcc send $nick %file
}