If you see this error, it means that your course is connecting via LTI; however, there is no data being sent that LTI can use.
This most commonly results from the command parameters not being set, or being set incorrectly.
Check your "custom parameters" (in some installations) or check to be sure that the correct parameters are being set as part of the URL.
The URL for each LTI tool instance (link) should have the following appended to it:
?command=report (for the "Course Management and Reporting" link)
?command=unit&unit=X (for each "Unit Map" link, where X = the unit number)