Em.. did you test this?
There's no $Regs in your command so it should be
ereg("<body>([</body>]{0,})</body>", $HTML,$Regs);
But what you are mathing does not makemuch sense to me:
ereg("<body>([</body>]{0,})</body>", $HTML);
Doesn't this return lines that start with "</body>"?
Anyway, it doesn't seem to work.