I don't have your same environment, but as far as I can tell you should point your finger at Win32::MMF::Shareable, not at Tk.
I've tried the following variation of your code: 
...
#use Win32::MMF::Shareable;
use ScalarTieTest;

print "Process starting...\n";

#my $ns = tie my $wait, 'Win32::MMF::Shareable', 'wait' or die;
my $ns = tie my $wait, 'ScalarTieTest', 'wait' or die;
...

[download]
where the module ScalarTieTest is just this quick'n'dirty hack: 
package ScalarTieTest;
use Carp;
use strict;

sub TIESCALAR {
 my $class = shift;
 my $scalar = shift;
 carp "ScalarTieTest::TIESCALAR($scalar)";
 return bless \$scalar, $class;
}

sub FETCH {
 my $self = shift;
 confess "wrong type" unless ref $self;
 croak "usage error" if @_;
 carp "ScalarTieTest::FETCH()";
 return $$self;
}

sub STORE {
 my $self = shift;
 confess "wrong type" unless ref $self;
 my $new_scalar = shift;
 croak "usage error" if @_;
 carp "ScalarTieTest::STORE($new_scalar)";

 $$self=$new_scalar;
 return $new_scalar;
}

1;

[download]
Everything runs fine on my Linux Perl 5.6.1: this leaves me thinking that if you want to go through the source of something, you'd better dig into your IPC module's internals. A good starting point could be to add debugging info to all of the FETCH/STORE operations of the module.
HTH,
Ant9000

In reply to Re: Tk and waitVariable on tied variables by ant9000
in thread Tk and waitVariable on tied variables by Roger

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