We just run into this problem and we found the answer. 

In the web.config file for the Portal you need to find and edit the following entry

<add type="SolidCP.Providers.ResultObjects.HeliconApeStatus, SolidCP.Providers.Base, Version=1.4.7.0, Culture=neutral, PublicKeyToken=da8782a6fc4d0081" />

If you change the version to match what you have upgraded to, 1.4.8.0, it works.

Hope this helps somebody else.

Regards

Mark Donne

HOST100 - www.host100.co.uk 

Worked like a charm, thanks!

Thank you Mark, your solution worked for me too.