We believe that your issue has been closed by the upload of
Version 0.9.29 of grml2usb from Michael Prokop <mika@grml.org>.
The explanation is attached below

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Hash: SHA1

Format: 1.8
Date: Thu, 25 Nov 2010 11:15:10 +0100
Source: grml2usb
Binary: grml2usb
Architecture: source all
Version: 0.9.29
Distribution: unstable
Urgency: low
Maintainer: Michael Prokop <mika@grml.org>
Changed-By: Michael Prokop <mika@grml.org>
Description: 
 grml2usb   - install grml system / ISO to usb device
Changes: 
 grml2usb (0.9.29) unstable; urgency=low
 .
   [ Thorsten Glaser ]
   * [601cc84] correct a pasto (it's 'grub.cfg')
   * [dc6a084] There is no /bin/bash on most operating systems.
   * [eb1a910] fix bsd4grml boot (loopback and regular)
 .
   [ Ulrich Dangel ]
   * [3cec649] Append new flavours to grml-version, do not only update
     existing versions
   * [35d64cf] Update version
   * [ff5be86] Improve logging message
 .
   [ Michael Prokop ]
   * [e32e549] Re-add mtools to Depends as they are just suggests of
     syslinux package - thanks to Michael Gissing for the bugreport.
     [Closes: issue905]
Checksums-Sha1: 
 2b6f56849b83c6ccf47cc9c92bedbdbed40130a8 884 grml2usb_0.9.29.dsc
 7159244175d729a36878a0003a9704505c6903a6 1242925 grml2usb_0.9.29.tar.gz
 b1079fcba341c176326ce9aea377972845ff25ea 866930 grml2usb_0.9.29_all.deb
Checksums-Sha256: 
 acb2b7ef8d567a24fb119d8f600d68ad3727a1b1c2331af1ba36327f8532798c 884 grml2usb_0.9.29.dsc
 d802521f30f2d312c69391857b3b15c5e447da907d8cc2bf01feea9d58b77dfa 1242925 grml2usb_0.9.29.tar.gz
 cfdd47a3ce86368a6c07cc84b43a04dadf6cbd97a7ca73ab815419aa7e5563bf 866930 grml2usb_0.9.29_all.deb
Files: 
 b4b83a6071931b8f2c71af9edda66598 884 grml optional grml2usb_0.9.29.dsc
 0c8b58cf100644eb83b4ef8cde01ef39 1242925 grml optional grml2usb_0.9.29.tar.gz
 1a86974d53e1da735d64432de56b77d3 866930 grml optional grml2usb_0.9.29_all.deb

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Reported by Michael Gissing on the grml user mailinglist:

I'm using grml2usb (0.9.25) from grml repo on a Debian Squeeze system. grml2usb 
fails with the message           

Installing syslinux as bootloader
sh: mcopy: not found
syslinux: failed to create ldlinux.sys

That's because syslinux package in Debian Squezze just 'suggests' mtools·
package. I filed a Bug in Debian BTS requesting syslinux at least to·
recommend mtools package but it was closed... (Bug#594331 [1])

Maybe grml2usb could catch this error and give a more user friendly explanation 
why the command failed.

[1] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=594331