[Forum] Error regarding form submission and UTF-8

[Zackw]

A user received the following error in what he calls a "subwindow" that appeared below our forum.

A form was submitted in the windows-1252 encoding which cannot encode all Unicode characters, so user input may get corrupted. To avoid this problem, the page should be changed so that the form is submitted in the UTF-8 encoding either by changing the encoding of the page itself to UTF-8 or by specifying accept-charset=utf-8 on the form element. newthread.php
This browser is AJAX compatible vbulletin-core.js:11:10737
Firing System Init vbulletin-core.js:11:26208
Fire vB_XHTML_Ready vbulletin-core.js:11:29535
Fetch Cookie :: vbulletin_collapse (null) vbulletin-core.js:11:17103
Fetch Cookie :: vbulletin_multiquote (null) vbulletin-core.js:11:17103
This site makes use of a SHA-1 Certificate; it's recommended you use certificates with signature algorithms that use hash functions stronger than SHA-1.[Learn More] www.facebook.com

Any info on this? Is there something to change to UTF-8 or a patch to convert to it? Is it a non-issue?
No idea where to start on this one.
VB 4.2.3