I have no problem with running your program on my machine, except it is scary to start so many threads. I killed it after 2500.

Here is a modified version of your program, which runs flawlessly (at 100% CPU) , and produces 5000 threads.

I'm on a Windows XP machine @ 1 GHZ, 1 G memory.
perl, v5.8.0 built for MSWin32-x86-multi-thread.

use strict;
use warnings;
use threads;

my $thread_count = 0;

for (1..5000) {
  threads->new(\&handle_thread,++$thread_count);
  sleep .1;
}
sleep 10;
print "--Parent Quits --";
######################
sub handle_thread {
    my $thread_count = shift;
    threads->self->detach;                # so long parent
    print "You are thread number $thread_count \n";
    sleep .2;
}
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