I've had this problem in two cases:
1) The indexing service is on. Try turning it off and see if the problem goes away. This is what your problem sounds like to me.
2) The context you are running under does not have write permissions to the $WINDOWSDIR$\TEMP directory. But since the temp dir doesn't appear anywhere in the trace, I would try the indexing service first.

Yeah they disabled indexing services on all servers.

I've been running into this more and more frequently lately. So far I have not found a valid fix. I've done everything from rebuilding the app project by project, removing the reference and adding it back in. Nothing seems to work 100% of the time, and I'm actually convinced none of it is doing any good. I had it go away once without doing anything but refreshing the page, and other times nothing short of a reboot would cause it to go away. I'd love to hear of someone who has actually found a resolution to this problem.

it's an issue with the xmlserializer namespace. Theres some code to check for the required permissions @ http://www.hanselman.com/blog/BruteForceCheckToEnsureAccessToTheTEMPDirectoryInOrderToUseTheXmlSerializer.aspx , but essentially you have to grant read & write permissions to $WINDOWSDIR$\TEMP as xmlserializer creates temporary assemblies there when used.

Hi
I was facing this problem when creating a webform to consume an external web service. After a lot of debugging the issue found was as follows:

The WSDL of the WebService has xsd:integer instead of xsd:int and also some of the element names were in the form tablename.fieldname. I changed it to just the field name ie <element name="fieldname">. After updating the web reference, the webform could be invoked sucessfully.

Regards
Visakh

This could be a general issue with .net I have the similar error with my VB application.

I had and issue similar to this and it was solved by fixing the permissions on the C:\WINDOWS\Temp folder, as described by this link here:

support.smartertools.com/.../KBArticle.aspx

Looking in task manager showed a large number of cmd.exe processes running (something to do with a dodgy scheduled task I think).  Rebooting solved both problems

thanks - I've had the same problem with an ASP.net application and changing the permissions on the C:\windows\temp directory fixed the issue. Dodgy microsoft software strikes again!!

We have a web app that gets this under certain circumstances.  Always related to write permissions. In my case its the IWam account.

Hey Guys and girls if any,

Have a look at this, it might help you. It solved my problem with: Exception Details: System.IO.FileNotFoundException: File or assembly name nwyqbbug, or one of its dependencies, was not found.

It listed as a Bug in microsoft's website.

The link:

support.microsoft.com/.../820126

Hey even i have got same issues..trying to serialize and deserialize a big xml ...

but finally could able to resolve it using the following tool.....

www.cybral.com/downloads.aspx a lot to the author of the tool...

You must give permission to the IIS user to the directory c:\windows\temp

Good Bye

Selim's suggestion about MS' bug report and the resolution there fixed my problem !! Thanks Selim.

Is it me or is it Microsoft....?

This File or Assmebly not found thingy is getting on my nerves

Correction to the smartertools KB link above about this error:

www.smartertools.com/.../troubleshooting-file-assembly-name-xxxxxxdll-one-its.aspx

Hi

From your error either the file nwyqbbug.dll is a third party dll, you are using within your code or a class library dll you created and you are calling within your project. If one of the above, then generally to solve this is to copy the dll into the bin folder Appbase=file:///D:/wwwroot/Forums/Web/Forum/bin

The problem was the permissions on the Windows\temp directory.

I have the same problem but but in my case, i have 2 different projects that use the same dll file. one of them works fine the other is giving this exception. Both projects are on the same pc. HELP!!!