Hello Sanjay,
Report "To Do List" is currently disabled in english/haengm.hal. If your customer has HAL package then this is what you can do:
1. Uncomment Report("To Do List",ActTodoRClass,ActTodoRn,0,modCRM); which will enable report to be shown in report list
2. System >> Access Rights >> Access group that should have access to it >> Report: To Do List, FULL
Our engine is designed in a way that it does not show Access Rights for things that are not enabled in UI.
I hope that helped!
Best Regards,
David D.