Blank page when trying to post an article and add a link

hi, same problem with me, really urgent! my blog was hacked, so i had to upgrade to 2.5. everything works fine, but when writing a post, after clicking on “Publish” or “save”, it will switch to the …post.php URL and show a blank site – finish! i can’t publish anymore.

thx for your help!!!

my blog is https://www.african-news.ch, due to the hack attack it’s not finally restored.