Creating a new module using vtlib 2.1 for vtiger CRM 5.0.4

I have created a new module in vtigerCRM using the vtlib 2.1 api doc as provided in the following link. http://wiki.vtiger.com/archives/index.php/Vtiger_CRM_5_Developer_Guide/VTLIB

Though the module appears to have been created successfully I am开发者_如何学Go getting the following error when I try to add a new record.

( ! ) WebServiceException: Permission to perform the operation is denied in C:\xampp\htdocs\dnbcrm\include\Webservices\Retrieve.php on line 30
Call Stack
#   Time    Memory  Function    Location
1   0.0037  338824  {main}( )   ..\index.php:0
2   0.8090  21393040    include( 'C:\xampp\htdocs\dnbcrm\modules\TargetModule\Save.php' )   ..\index.php:693
3   0.8209  21498512    CRMEntity->save( )  ..\Save.php:21
4   0.9772  23107304    VTEventsManager->triggerEvent( )    ..\CRMEntity.php:859
5   0.9773  23107304    VTEventTrigger->trigger( )  ..\VTEventsManager.inc:118
6   1.0133  23415848    VTWorkflowEventHandler->handleEvent( )  ..\VTEventTrigger.inc:119
7   1.0218  23433280    VTEntityCache->forId( ) ..\VTEventHandler.inc:51
8   1.0218  23433600    VTWorkflowEntity->__construct( )    ..\VTEntityCache.inc:83
9   1.0218  23433992    vtws_retrieve( )    ..\VTEntityCache.inc:16

People around the Internet state to issue a Vtiger_Module::initWebservice() to solve this problem, but actually it didn't work for me. Anyway try it out, maybe you'll be luckier than me.