Just wondering, but does the webserver have privileges to edit the script? If not, then that's your problem.

Of course, what you're doing is pretty pointless. If you're running this script on someone else's machine, they can just take the script and decode it themselves. In this case, get a host you can trust not to look at your stuff. If it's on your machine, then that's just so hilarious that I can hardly continue typing. If this is your security policy, might I suggest investing in a new one. I'm not trying to be a troll. Acme::Bleach is nice to look at and nice to show perl programmers just starting out, but it is not meant to be taken as a serious form of security.

antirice    
The first rule of Perl club is - use Perl
The ith rule of Perl club is - follow rule i - 1 for i > 1