The issue usually occurs if you are missing the required assembly or missing some entry in the web.config.

The required entry in the web.config is already listed in the article "IIS 6 and IIS 7 Integrated mode support" on the WebTextEditor documentation. If you are using IIS7 you are still missing some entry in the system.webServer node.

The required assembly for WebFileUploader is:

- ISNet.dll
- ISNet.WebUI.dll
- ISNet.WebUI.Resources.dll
- ISNet.WebUI.WebTextEditor.dll
- ISNet.WebUI.WebTextEditor.Resources.dll

If none of the suggestion solve the issue please send us the simple page and the web.config you are using. 

I'm having the same problem.  I have included my sample solution.

I send you an example here and the web config, for me the same error keeps coming

Analysing your attached web.config, it seems you are using IIS7 and as I mentioned previously if you are using IIS7 you are still missing some entry that has been detailed in the article "IIS 6 and IIS 7 Integrated mode support" on the WebTextEditor documentation.

The missing entry is WebFileUploader handler in <handlers> and <modules> section under <system.webServer>. Below is an excerpt from the documentation:

The following configuration applies for ASP.NET application that target IIS 7.
- Add WebFileUploader hander to <handlers> section under <system.webServer>:
  <add name = "WebFileUploaderHttpHandler" verb="GET" path="WebFileUploaderHttpHandler.axd" type="ISNet.WebUI.WebTextEditor.WebFileUploaderHttpHandler, ISNet.WebUI.WebTextEditor" preCondition="integratedMode" />
- Add WebFileUploader module to <modules> section under <system.webServer>:
  <add name = "WebFileUploaderHttpModule" preCondition="managedHandler" type="ISNet.WebUI.WebTextEditor.WebFileUploaderHttpModule, ISNet.WebUI.WebTextEditor">

i'm include this .dll's

- ISNet.dll
- ISNet.WebUI.dll
- ISNet.WebUI.Resources.dll
- ISNet.WebUI.WebTextEditor.dll
- ISNet.WebUI.WebTextEditor.Resources.dll

and i'm using windows web server 2008, I have the web config and modifying sensitive me the same error keeps coming, please give me a example.

Based on my analysis of the new web.config, you move the <httpHandlers> and <httpModules> entry to the <handlers> and <modules> under <system.webServer>.

In order to run the file uploader successfully in IIS 7 you will need all the entry in <httpHandlers>, <httpModules>, <handlers>, and <modules>. This has been detailed in the article titled "How-to: Configure WebFileUploader for IIS 7 application" on the WebTextEditor documentation

I'm still having the same issue when I put the two missing entry's in this reference:

The missing entry is WebFileUploader handler in <handlers> and <modules> section under <system.webServer>. Below is an excerpt from the documentation:

Note:  I was able to run your examples.  It's one of the reasons, why I followed the previous format versus this one.

The following configuration applies for ASP.NET application that target IIS 7.
- Add WebFileUploader hander to <handlers> section under <system.webServer>:
  <add name = "WebFileUploaderHttpHandler" verb="GET" path="WebFileUploaderHttpHandler.axd" type="ISNet.WebUI.WebTextEditor.WebFileUploaderHttpHandler, ISNet.WebUI.WebTextEditor" preCondition="integratedMode" />
- Add WebFileUploader module to <modules> section under <system.webServer>:
  <add name = "WebFileUploaderHttpModule" preCondition="managedHandler" type="ISNet.WebUI.WebTextEditor.WebFileUploaderHttpModule, ISNet.WebUI.WebTextEditor">

From my analysis of your attached project, the solution is the same with my previous post. In order to sucessfully run the WebFileUploader you will need to add WebFileUploader entry in <httpHandlers>, <httpModules>, <handlers>, and <modules>. This has been detailed in the article titled "How-to: Configure WebFileUploader for IIS 7 application" on the WebTextEditor documentation.

In your attached project you are missing WebFileUploader entry in <httpHandlers> and <httpModules>

Hello,

I'm experiencing the same issue on my development workstation (Windows XP, IIS 5.1).

I attached an extract of my web.config and the user control I'm using. I also did the references to all required assemblies:

- ISNet.dll
- ISNet.WebUI.dll
- ISNet.WebUI.Resources.dll
- ISNet.WebUI.WebTextEditor.dll
- ISNet.WebUI.WebTextEditor.Resources.dll

Do you have any idea why it is not working?

Nicolas

Based on my analysis, you are using the same WebTextEditor snippet in the IntegrationWithWebFileUploader.aspx sample. Does the sample runs without any issue on the workstation?

I also notice that you are using a third party smart panel control, do you mind testing the sample without the smart panel to determine this is not a compatibility issue?