There are some problems with the code here. First, you need to make sure that you are keeping the hash %values separate from the scalar $value. Secondly, I'd move the foreach outside the while or you will be getting quite a lot of repetitive output.
Try this as a quick rewrite.

my %values;

while (<INFILE>){
    chomp;
    next unless (/\t/);
    my ($key, $value ) = split(/\t/, $_, 2);
    $values{$key}=$value;
}

foreach my  $key (sort keys %values) {
    print OUTPUT "$key: $values{$key}\n";
}
[download]

If you'd rather just log it as the file is read you can get rid of the foreach and move the print statement back inside the while.