[TheLastSuperman]

Check the files on your server, in the same folder your vbulletin is running from, is there an empty index.html file present? It looks like from the pages source code, that this is being called by a plugin or was edited into the style (not in the version uploaded here though so i.e. you might have been hacked at some point in time, that's the only reason to include an invisible iframe usually but why is it being directed to include a 1kb blank.html file ? very odd imho).

This is found when I view the source code for your forum:

PHP Code:

    <iframe id="yui-history-iframe" src="clientscript/yui/history/assets/blank.html"
            style="position:absolute;top:0; left:0;width:1px; height:1px;visibility:hidden;"></iframe>
    <input id="yui-history-field" type="hidden" /> 


Makes no sense to link to an iframe in a 1kb file like that unless it was compromised but then the file size if it contained mal code should be larger than the original file size, which is the same 1kb so odd all around I'd say, can't tell anything specific unless I had access and I'm booked for the night working now and its close to 11pm here so no time to check regardless and not trying to scare you one bit simply saying this seems very odd and that you need to look into it to be safe.

I would replace default vBulletin files to be safe, check in the admincp using suspect file versions under maintenance after replacing them and also check for spare admin accounts. If anything looks odd file-wise then make a new thread in the vB4 forums and ask for feedback/assistance w/ the file names before deleting. *As always make a backup of database and files before removing anything.

Edit: Who is pasting <table and <TR <TD codes all over the place? STOP DAT lol its just an old outdated way to design web pages... it still works but not the standard, only use when absolutely required i.e. you're pulling your hair out because you can't find a way to make something display properly so you cheat and use a table (try not to!). Just one of many examples explaining more in detail - http://www.itegritygroup.com/css-vs-tables/ AND here is an example of how to do a three part fluid header instead of using a table to do the same in vBulletin - https://vborg.vbsupport.ru/showthread.php?t=228319