RESOLVED runtime newer than the currently loaded runtime and cannot be loaded

Do you know what does this error mean? I did a rebuild on my  local machine and uploaded all files, but i still get:

Server Error in '/' Application.
--------------------------------------------------------------------------------

Could not load file or assembly 'AjaxControlToolkit' or one of its dependencies. This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded.

Is it my server that is running an old version of some kind?

you can se the full error on www.slikfabrikken.dk


Thanks

Replace the file 'AjaxControlToolkit' on the server again. (Perhaps the file was copied with errors)

Just tried it. Same thing. Is it .NET version issue? My host is running ASP.NET 4.0

Are you sure that the current virtual directory in your host is running in .net 4?

My site is back online. As soon as it was set to run .NET 4.0 integrated mode it worked.
Thanks.

i have the same issue. how do you enable the  ".NET 4.0 integrated mode" im running windows server 2008 with IIS7.

you should be able to set this from your hosting companies control panel - who are you hosting with ?

I get the same error installing nopcommerce 1.9 in iis 6, anyway to fix this? I´ve got complete control over the server

I just got the same error on 1.9, Windows Server 2003, II6