Hi guys,

 This error will come when a reference is specified in web.config and deployment folder/site does not contain these dlls installed in the system or bin folder does not contain them(if they are private assemblies). 

<add assembly="Namespace1.NameSpace2, Version=x.x.x.x, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>

if your web.config contains any assemblies like this and deployed server doesnot contain these assembiles in bin or GAC, then this error will occur.

Best,
Venkat

Yes that solved the issue for me. I still had seme references to some Infragistics controls in a site and they are not in the GAC on the server. Thanks for your help.

 mmm i had the same or similar problem

i had a published website and web application project containing some ascx controls and the dll of the published web application project these ascx controls will be loaded at runtime in the website

The problem:

When the website was published ..The "make this website updatable " option was not marked so the published version of my web application project couldn't be merged with the website at runtime

 Solution:

If u have the same problem make sure to choose make this website updatable when publishing

Hi I got the problem with has not been pre-compilied, even if i put the right assemblys and dll I still get the problem.

 Finally i choose the last option of the Deployment ("Create a separate assembly for each page and control output"), whit this the deplolyment makes the site like if i publish the site.

 I tested my setup and works fine now.

The scenario of the server was Win 2003 server, framework 2.0, ajax beta (When the dll's used to have the namespaces Microsoft.Web:Extensions) instaled on the server but the site use the dll's of the new ajax, IIS 6.

Hopes this will be helpful for someone. See ya