Hi askaggs,
Based on the error message, you need to verify if the this ID has been included the Office 365 ProPlus license.
To do this, you can try to reproduce this issue on another computer. (The Windows system can also install the Office 365 ProPlus. It is the Office 2013 version)
In addition, for the questions about Office 2011 for Mac, we offer a specific support channel for our users. You may reach the support by the following link:
http://answers.microsoft.com/en-us/mac?auth=1
Thanks for your understanding.
Regards,
Wilfred