It's probably better to name your libraries '.pm' instead of '.lib'. Not only can they then be 'use'd properly, but it's really better to conform to existing standards than to invent your own.

One of the problems with eval is that it can hide errors. Don't forget to check $@ for anything you might have missed.

Also, in the context of your gethash function you can use an actual hash, and return a reference to it. Saves having to dereference repeatedly. With a tiny bit of tweaking, you get:

# hash.lib
# in the library

sub gethash {
  my %hash;
  open(FILE, "data.txt") || die "Can't open data - $!\n";
  # dick:98
  # robert:76
  # mary:68
  chomp(my @lines = <FILE>);
  close(FILE);
  foreach (@lines) {
    my ($name,$score) = split /:/, $_;
      $hash{name}  = $name;
      $hash{score} = $score;
  }
  return \%hash;
}
[download]

More tweaking produces:

# hash.lib
# in the library

sub gethash {
  open(FILE, "data.txt") || die "Can't open data - $!\n";

  my %hash = map { (split(/:/))[0,1] } chomp(<FILE>);
  close(FILE);

  return \%hash;
}
[download]