[Greasemonkey] Problem with extension generated from GM script

[Edward Hibbert]

I've just discovered Greasemonkey - splendid thing.  I wrote an
extension to help make moderating Yahoo groups easier, and after a while
turned it into an extension using the compiler at
http://www.arantius.com/misc/greasemonkey/script-compiler.php.
 
This works fine for me, and for a couple of other people - but not for
quite a lot of others, including for people for whom the
Greasemonkey/script combination worked.  So far as I can tell, the
extension isn't firing at all - if I put some dump() calls into the
script-compiler.js file, and set Firefox's properties so that it should
come out in the console, then I don't see anything on the machines which
aren't working (but I do on mine).
 
I had a similar problem when I first tried this, when I used the
compiler at http://www.letitblog.com/greasemonkey-compiler/.  This makes
me wonder whether I'm using the right compiler.
 
Otherwise I'm at a loss to know what to try next.  Any thoughts?
 
Thanks,
 
Edward.