Compiler censorship? In my Drupal?

I don't know what the hell is going on, but if I enter "g plus plus" (no quotes, no spaces, plus replaced with plus sign), followed by a space followed by anything, my own blog gives me a 403 permission denied error!

I'd lodge a bug report, but to whom? Drupal, which has a million layers which may or may not be responsible for this? The GeSHi plugin for Drupal? GeSHi itself? The old, outdated PHP 4 installation? I don't have the will to debug yet more web crap, so I'll just post "around" it, if that's even possible.

Incidentally, that's why I haven't posted in a while: this error in a long blog post fooled me into thinking I couldn't post to my own blog. I'll post something I've kept on the back-burner right away.