A bit of search and I found something about a previous different issue with iBrowse:
http://eab.abime.net/showthread.php?t=14607
I am not sure that RCK or anyone here can do anything to solve your issue exoticaga (and daxb apparently too).
So, the best way would be to mention the issue to the iBrowse developers. They will then check if there is an issue with some of their code. Then if the issue is with vbulletin they will report it to vbulletin developers or ask you to report it to vbulletin (or have RCK report it).