title: Testlink login error
body: <p>I have installed and configured testlink 1.9.16 on centos7 server using following link 
  <a href="https://sysadmin.compxtreme.ro/how-to-install-testlink-on-centos-6-3/" rel="nofollow noreferrer">https://sysadmin.compxtreme.ro/how-to-install-testlink-on-centos-6-3/</a></p>
  
  <p>I made some changes according to my Centos7</p>
  
  <p>after completing all procedure, when i open <strong>IP_of_my_server/login.php</strong>
  i get following error message</p>
  
  <p>============================================================================== 
   DB Access Error - debug_print_backtrace() OUTPUT START 
   ATTENTION: Enabling more debug info will produce path disclosure weakness (CWE-200) 
              Having this additional Information could be useful for reporting 
              issue to development TEAM. 
   ============================================================================== </p>
  
  <p>my log entry is</p>
  
  <p><strong>ERROR ON exec_query() - database.class.php <br /> -  - /* Class:tlEvent -  Method: writeToDB */ INSERT INTO events</strong> </p>
  
  <p><strong>(transaction_id,log_level,description,source,fired_at,object_id,object_type,activity) VALUES (0,2,'','',1503033721,0,NULL,'')<br />THE MESSAGE : /* Class:tlEvent - Method: writeToDB */ INSERT INTO events</strong> <strong>(transaction_id,log_level,description,source,fired_at,object_id,object_type,activity) VALUES (0,2,'','',1503033721,0,NULL,'')
  Query failed: errorcode[]
          errormsg:</strong></p>
  
  <p>My mysql version is <strong>mysql  Ver 5.6.37 for Linux on x86_64</strong> 
  and my PHP version is <strong>PHP 5.6.31 (cli)</strong></p>
  
  <p>can anyone help me ?</p>