question about mod_ssl + apache + POST

[trek]

This is what I have running

Apache/2.0.51 (Win32) mod_ssl/2.0.51 OpenSSL/0.9.7d PHP/5.0.0 Server at localhost Port 443

I have a page https://localhost/test.php that has a form on it, the form method is POST.
When I submit the page with firefox, 9 times out of 10 it works fine. Every once in a while
I get

Method Not Allowed
The requested method POST is not allowed for the URL /test.php

With IE I get that every single time.

So I'm a little confused. I was reading a little bit and it seems mod_ssl isn't too friendly with
POST, but I don't see why the browser matters. If anyone could clear this up it would be great.