To grant users access to the app you'll need to provide their assigned user profile access to the app's custom object, Apex Classes, and Visualforce Pages.
1. Setup / Manage Users / Profiles / Click the appropriate user profile.
2. Click 'Edit'
3. Select "Visible" for Timba Surveys and then Save
4. Go back to Profile Overview and click on Object Settings.
5.Scroll down and select Timba Surveys.
6.Click Edit and select "Default On" and then Save.
7.Go back to Object Settings and click on AnswerOptions
8. Click edit
9. Select the Object Permissions and grant "Visible" permissions to all fields and then Save
10. Repeat steps 7, 8 and 9 for the following objects:
- Question Images
- Question Summaries
11. Scroll or click the Apex Classes shortcut at top of page
12. Click Edit and move Apex Classes from Available to Enabled. It is possible you need to scroll with your keybord arrows.