It was not.  I had used your earlier instructions:

 

"  <appSettings>
  ...
   <add key="ConnectionString" value="server=(local)\portal;database=SamplePortal;uid=test;pwd=test"/>
  <add key="CuteChat.ConnectionStringProvider" value="SamplePortal.ConnectionStringProvider,SamplePortal"/>
  </appSettings> "

 

I changed it back to your latest instructions and it still produces the same error.

 

What should the value be?  Is it <database>.ConnectionStringProvider,<database> or is "CuteChatControls" or "SamplePortal" arbitrary values?