We have a dotnetnuke site that hosts 3 portals. Recently I attempted to upgrade to version 6 from 5.6.3.. Thad did not go well as the site started throwing errors and we couldn't get in. The problem turned out to be a Telrik dll with the wrong version. Before tracking that down I rolled back the upgrade. I got the site back up by placing a newer version of the Telrik dll on the site which seems to be the cause of the upgrade problem according to the info on this and other sites.

After getting the site working again, atleast showing the pages I tried to update some content using the rtf module. This throws and error and looking in the logs I see "DotNetNuke.Services.Exceptions.ModuleLoadException: Unknown server tag 'dnnweb:DnnImage" There is a page of stack trace but the basic message is about the unknown server tag  I can't edit any content as it is and don't know where to look to fix this. I am afraid to try and upgrade again as that seemed to be the start of the problem.

Any suggestions on how to fix this problem would be greatly appreciated.

Doug