This is a very odd construct: while (<@list>){Are you sure it's what you intended? What do you think it's going to do? What's in @list when you run this code?

Also, this line makes me think you're converting a shell script or an awk program: if ("$prolist{$val}" eq "$_" ){since quoting those variables is unnecessary.

With those warning signs, I don't want to hazard a guess on what might be wrong. Could you provide some more info on what you're trying to do and what doesn't go the way you intended?