Without looking at the code the stylesheet probabbly uses text-align:center; to center content in ie. This is actually incorrect and does not work on any modern standards-complient browser.
Try using this method alongside your original code:
https://bluerobot.com/web/css/center1.html
If all else fails the old-school <center></center> HTML tags work on most browsers (but aren’t officially supported – so may behave erraticly)
