A user gets an NPE when trying to access a forum from the Lessons page. To reproduce:
-Create a new site
-Add Lessons and Forums tools
-Go into Forums, click General Discussion and Start a New Conversion
-Enter Title and Message, then click Post
-Go into Lessons, and click Add Content
-Choose "Link to a forum or topic"
-Click "Use Selected Item" (it will default to the forum topic added above)
-On the Lessons page, click the link that was just created.
-Bug report for NPE will appear
See attached stack trace.