[SOLVED]Charts not displayed

[istream]

In my current environment

• RHEL 5
  MySQL 5.1.50
  Apache 2.2
  PHP 5.3.3
  Testlink 1.9 Beta 5
  Bugzilla 3.6.2

When i Click on Charts, nothing is displayed on the right hand side, however the log shows following:

• WARNING E_WARNING require_once(/usr/local/testlink/cfg/.cfg.php): failed to open stream: No such file or directory - in /usr/local/testlink/lib/bugtracking/int_bugtracking.php - Line 367
  WARNING E_NOTICE Undefined variable: g_interface_bugs - in /usr/local/testlink/lib/bugtracking/int_bugtracking.php - Line 363

the bugzilla interface from testlink is working fine, i.e. I can create new bug, add it to failed test case, browse to the link of the bug from testlink.
The gd module is there in phpInfo.
HELP HELP.
Thanks

[istream]

I have no luck with this, yet, can anyone, may help me out with some hint, where to look?
Thanks

[istream]

On more checking, the file int_bugtracking.php actually had the line

$btsname = strtolower($g_interface_bugs);
Changed it to following
$btsname = strtolower($bts_type);
==============================
Charts are working now.