> It looks to work well if I launch the script from bash. But if I try to 
> run amcheck, it gives me following error:
> 
> ERROR: www-dev: [GNUTAR program not available]

Have you checked amanda debug files (in /tmp/amanda)? It should tell
you what program Amanda is callin GNUTAR.

Did you rebuild Amanda using the new path of your script in
/usr/local/bin?

Olivier