Kindly fix this issue,When I clicked the bug icon in the Testlink screen I got this isssue.
Fatal error: Call to a member function getEnterBugURL() on a non-object in D:\ProgramFiles\Apache Software Foundation\Apache2.2\htdocs\testlink\lib\execute\bug_add.php on line 42
Ok, but there is not enough information to warrant a "fix", because it is not clear, based on your detail, that a bug tracking system has been setup for use with TestLink.
Know that there is NOT a default bug tracker configuration [which will definitely cause that message], as one must be specified AND configured for use.
So, check the documentation, and post again if there may be more questions.