Here's how I would tackle the task:

#! perl -slw
use strict;
use threads;
use threads::shared;
use Thread::Queue;
use constant EXPECTED_SIZE => 244812;

my( $path, $T ) = @ARGV;

my $Q = new Thread::Queue;
my $sem :shared;

my @threads = map{
    async {
        while( my $file = $Q->dequeue ) {
            my $count = `bzcat $file | wc -l`;
            if( $count != EXPECTED_SIZE ) {
                lock $sem;
                warn "$file: $count\n";
            }
        }
    }
}  1 .. $T;


$Q->enqueue( glob $path );
$Q->enqueue( (undef) x $T );

$_->join for @threads;

__END__
901213 \test\*.bz2 8 2> your.log
[download]

Should run anywhere you have a threaded perl. The second command line argument is the number of concurrent processes to run.