Failed to create a 'Settings' from the text 'Ass

We got this error message in a popup window when accessing some back-end pages, such as Amdin -> Pages.
Now we cannot do modifications on our page contents.

Does anyone found similar errors before?

Please help.

Hi Devin,

Can you give me more details about your project - is it new or upgraded? Have you done any customizations (controls, widgets) ? Also can you use Firebug and check what error is coming up? Can you tell me what actions have you taken prior to the error? Have you tried to reproduce it in a blank new project ( if your current one has been modified ).

Regards,
Victor Velev
the Telerik team

Hi,

For those who've searched for this error and need a solution (as I did):

I was also receiving the same error in the same circumstances. The actual error was

Could not load file or assembly 'Telerik.OpenAccess, Version=2012.3.1012.1, Culture=neutral, PublicKeyToken=7ce17eeaf1d59342' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Telerik.OpenAccess" publicKeyToken="7ce17eeaf1d59342" culture="neutral"/>
        <bindingRedirect oldVersion="2012.3.1012.1" newVersion="2012.2.628.2"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

Just to let you know, i got this error when i configured log4net in my Sitefinity project but i forgot to include the log4net.dll in my project bin. After copying the file the problem was gone. 

A .dll problem here too.
I did not know that until took a look in error.log file (App_Data\Sitefinity\Logs\Error.log) where i found 
Inner Exception
---------------
Type : System.IO.FileNotFoundException, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
Message : Could not load file or assembly 'vjscor, Version=1.0.3300.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The system cannot find the file specified.

After including   <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <probing privatePath="bin;bin\HttpModules;bin\Providers;bin\Modules;bin\Support;"/>
      <dependentAssembly>
        <assemblyIdentity name="vjscor" publicKeyToken="b03f5f7f11d50a3a"/>
        <bindingRedirect oldVersion="1.0.0.0-1.0.5000.0" newVersion="2.0.0.0"/>
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

in web.config, everything is fine now.