When viewing some threads in the PHP forum, My Norton Internet Security blocked intrusions with the following details:
Intrusion: HTTP TIF Folder Info. Disclosure.
Intruder: 69.20.16.232(http(80))

I found this occurs on (some) threads with PHP script displayed (though the code was enclosed in the forum php tags)
I also noticed it occurs when editing a post which contains php code, but only in the quick edit, not from the advanced view.

For a specific example, it occurrs when editing the first post in
http://www.sitepoint.com/forums/showthread.php?t=485436