If you're positive that the warning has no real effect & you just don't want to see it being printed, you can always use a hack like this:

 
{local $^W=0;
   #stuff that throws the warning here
}
[download]

of course, it's always better to figure out why the warning is being thrown than just suppressing it because you don't want to see it, and there's probably a much better way to deal with this.

You migh want to check this out: Switch off warning for UNIVERSAL::AUTOLOAD