I want to suppress Following error line in my webpage in testlink : " DB Access Error - debug_print_backtrace() OUTPUT START "

I want to suppress Following error line in my webpage in testlink : " DB
Access Error - debug_print_backtrace() OUTPUT START "

enter image description hereI have installed testlink 1.9.7 with php 5.2
version. While serching for a particular testcase (which actually doesnot
exist) , I am getting follwing error or you may say debuging steps which
ultimately not showing anything else below it .
The lines are like this
DB Access Error - debug_print_backtrace() OUTPUT START
==============================================================================
==============================================================================
==============================================================================
DB Access Error - debug_print_backtrace() OUTPUT START
==============================================================================
==============================================================================
All other funcunalities are working fine. So I really don't want these two
lines to come like this and I want to suppress these lines.
I have attached a screenshot with the below hyperlink. I need an
experience php guy who can help how to stop these lines. Plz help.