Although, as much as I hate to remind it, my first suggestion would be to 'use strict' in your code. I've tried running your script with 'use strict' and it brought up a hoard of errors and warnings. I'm not, however, implying that this may be the cause of your troubles, but there's still a lot of 'unknowns' and blind spots left if you don't use the strict pragma in your code.

Update:

From the system manpage, you may try retrieve a little bit more info on the specific error of the ImageMagic script like so:

    my $sys_res = system("identify -verbose $DIR[$a] >> $dump");

    if ($sys_res) {
      # an error occurred!
      my $exit_value  = $? >> 8;
      my $signal_num  = $? & 127;
      my $dumped_core = $? & 128;  
      die "system failed: $exit_value, $signal_num, $dumped_core!"  
    }
[download]

You also say,

The problem occurs with a few files that are bad and bring down the programme.

Do you mean the system() call causes your actual script to terminate, not only the ImageMagic script? Please verify. Frankly, I never came across a problem where a call to the system() function would kill the parent process. Maybe that it is implemented differently on the Win 32 platform as it doesn't do 'forking' quite well or differently.

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