If you do not wish users to access a particular report in a folder, you may do so by disabling the report under permission assigned to the user.

Log into Web TimeSheet with administrative privileges.
Click on Administration tab in the top menu.
Select Permission under Users/Departments. The List Permissions page appears.
Click the Edit button next to the permission assigned to the user.
On Edit Permissions page, click on reports tab.
Click the '+' sign next to required reports section ( Example: Time Reports) to expand.
Uncheck box next to the report which needs to be disabled for the user
Click on Save.

Note:
When a permission is edited and changed, it affects all the users, who have this permission enabled.