If you want to resolve this, your going to have to post some code as Nitrox suggested. And also identify which version of AS perl your using?

I tried various things to try and re-create your scenario, but never came close. It just works. The only tim e I get any error is if I allow the parent to exit before the child resulting in the familar "A thread exited while 2 other threads were still running." msg.

#! perl -slw
use strict;
use threads;

my $kid = threads->new( sub{ system 'notepad.exe', 'd:\test.txt'; } );

print 'Parent detaching';
print $kid->detach;
print 'Parent waiting';
<>;
print 'Parent finishing...';
__END__
D:\Perl\test>test
Parent detaching
Parent waiting
^Z
Parent finishing...
[download]

Also, is it possible that the parent thread is ending before your detached thread is?

-Nitrox

No, the parent is still running. In a main routine, I create a thread that launches notepad.exe to edit a file. Then I do the detach. When I exit notepad, I get the error. I have other code in the same program that exhibits the same behavior.