Strange problem

I have an ASP.Net web application that runs fine on my local server but when I try to run it over the web I get the message:

Runtime Error
Description: An application error occurred on the server. The current custom error settings for this application prevent the details of the application error from being viewed remotely (for security reasons). It could, however, be viewed by browsers running on the local server machine.

Details: To enable the details of this specific error message to be viewable on remote machines, please create a <customErrors> tag within a "web.config" configuration file located in the root directory of the current web application. This <customErrors> tag should then have its "mode" attribute set to "Off".

<!-- Web.Config Configuration File --
<configuration>
<system.web>
<customErrors mode="Off"/>
</system.web>
</configuration
I have custom errors turned to Off...

Any suggestions?I think I know what it is:

Try going into teh problem server's IIS and find the application directory.
Then click properties on the directory.
When a dialog appears, click the 'Create' button next to trhe Application settings to create the application dir in IIS.

That should fix it.
Are you talking about Application settings in the Home Directory Tab of the properties?

If so then an application it is already set at the default application. I tried removing it and creating it again but no go.
I am talking about the directory where your code is.

Should be the directory where your 'bin' directory is.

That directory needs to be set as the application directory by doing the above steps I mentioned. This might no be the problem but the symptoms are similar to a problem I recently had and it was caused by me not doing those steps on the live server when I copied my files over.
I will try to explain it more clearly:

1) Open IIS
2) Find your application directory within IIS (usually somewhere in 'Default Web Site').
3) Once you have found the directory (it should have a bin directory in it), right click on it and a select properties.
4) A window should appear with a title of: 'you directory name' Properties
5) There should be a punch of tabbed pages. The first one having the title of 'Directory'.
6) Click the 'Create' button to create the Application name.
7) Click apply.

BTW these steps are based on IIS 6.0

This might not be the problem but to me it sounds like it is. Let me know how it turns out.
Not sure if this is the same thing but this is what I did:

1. Open IIS
2. Find my website that I have created
3. Right Clicked on it and selected properties
4. It has a bunch of tabs including Home Directory, WebSite, Directory Security etc
5. I go to Home Directory and click Create At the Application Settings.
6 The Application name is then created and I hit apply.
7. This I have tried a number of times but still get the same error message.
Well if that didn't fix I am not sure what else to suggest.

Do you have access to the server? If so use the local browser on it to test and see if it gives you an error message. It must be a configuration problem or something you missed when copying over the needed files since it works fine on your dev pc.