In some browsers, you see the character  somewhere in your forum, often in the upper left. This is a UTF-8 "Byte Order Mark". It got into one of your forum files when somebody editted and saved that file while editing in UTF-8 mode Microsoft editors are often blamed for adding this mark at the beginning of files.

To solve this problem:

1. Figure out which files have recently been edited
2. Once you find the file causing the problem, you would need to resave the file without BOM, you would need a decent text editor like notepad++ to do this.
3. If you need to edit the file in UTF-8 mode, use an editor which will allow you to "save without Byte Order Mark"