Date Problem

Hi,
I have searched and cant find an answer to my problem, I am using the classifieds theme and seem to have a date problem, When i try and use a plugin that uses a date picker the them trys to reformat the date incorrectly. I have tried setting the date in the settings to every possible setting i can find and still have the same issue. I have disabled every plugin and still have the same issue. I have tested the plugins in question on other themes and do not have this issue, so something in the them appears to be causing a problem from what I can work out.

I need to be able to use dd/mm/yy in the end product but at the moment testing with every format seems to create the problem.

Any help would be apreciated

Thanks
Simon