php code in post remove sidebar even with exec-php installed

each time I create a post with php code, the sidebar and footer will go off since I installed this theme – http://ww.wp.xz.cn/support/theme/annotum-sans even with exec-php installed. I always go away with this problem creating my post in default theme then returned back to http://ww.wp.xz.cn/support/theme/annotum-sans. Pls can some one help me out?
I have exec-PHP installed and it has been working fine
http://www.igalapedia.com