The following error happens because some old settings from a previous version of the Help Desk are still hiding in the background. Removing and adding the island back will clean up the code.
<Message><![CDATA[Object reference not set to an instance of an object.]]></Message>
1. Find the help desk causing the error.
2. Open configure island
3. Write down all the settings for this help desk island
4. Delete the island
5. Add back a Submit Help Desk Request island
6. Open configure island
7. Change the settings back to what you noted down in step 3.
The error will now go away in the log.