When using the forum module on my site, everything seems to be working fine except for one thing: whenever I try to post something on the forum while using Internet Explorer (8), I get an "HTTP 400 Bad Request." I am not having this problem in either Firefox or Safari. What is the problem here, and how can I fix it?
EDIT: When I turn off friendly HTTP error messages, it says, "SecurityID doesn't match, possible CSRF attack."
EDIT #2: After some fiddling around, I discovered where the error is thrown, and why: in the "httpSubmission" function within the "sapphire\forms\Form.php" file, $vars ends up containing no SecurityID value (it's also lacking a ThreadID value and an ID value). I still don't know why this is happening, or what to do about it, though.