White screen when trying to edit comments
 

Please let me know how to solve this problem

Not sure what your issue would be I can edit a comment fine without any problems so we would need more information.

I'am following the edit button at the right below corner which follows me to the url classifieds/comments.php?product=10&cedit=6
Then being click, submit edit- it give me white screen with the follow URL /classifieds/comments.php
Also the problem with RSS feeds, it is also white screen

Do you actually want to place a url so we can assist and a test login is needed also. ;) Your definately not reporting an issue in the software there has to be some external cause for you. When I edit a comment the url is like this so your missing all your variables.

mysite.com/classifieds/comments.php?product=139&cedit=37

The IE explorer give the 500 error, where I can send the test login info?

Feel free to send any site details to the contact us link in the header.