custom multipart-upload freaks out Linux... (one execve problem, the other 403 permanent)

This is a wierd situation...

Background (machine 1)

I have a custom multipart-form handler running in PHP on an Apache
server
Apache/2.2.0 (Unix) mod_ssl/2.2.0 OpenSSL/0.9.7a PHP/5.1.4
Server at xxxxx Port 80
It's on Linux
Linux xxxxxx 2.4.20-8 #1 Thu Mar 13 17:54:28 EST 2003 i686
i686 i386 GNU/Linux

And I was debugging the handler when *poof* the server started
suddenly giving me 403 "permission denied" messages. But this was
working just moments before. I have tried
a) starting and stopping apache
b) moving the htdocs area to a new place on the disk (restoring the
original)
c) rebuilt apache and php
d) rebooted the mache
And still the machine always responds "403" - This is not a
permissions issue, it certainly feels like something buffer overran and
changed something in the system config.

I had another box (a Suse linux 9.3 - or .2 box) which suddenly
freaked out as well, now it will do things like

central:~ # man man
execve: Permission denied

Anyone seen this before? Any ideas on what to check? I have been
checking disks, stracing, rebuilding for the last few hours, and can't
figure out how to get things working. It certainly does feel like some
config bit has changed.

Sincerely,
Blake