I was configuring my Rails application/project as instructed in the following article.

10-steps-to-get-Ruby-on-Rails-running-on-Windows-with-IIS-FastCGI

However, at the 10th step, i was not able to view the contents of the about controller. The output would always be "500 Internal Server Error"

I faced similar issue when i first deployed my .NET project in way back 2001/2002.

It boils down to folder permission (security) for the rails project. You have to give permission to IIS_WPG / NETWORK SERVICE.

Hopefully the following steps would resolve your issue. As for me everything is fine after configuring the same.

Step 1: Click start, click Windows Explorer, and select your Rails project folder.

Step 2: Right click -> then select "Sharing and Security"

Note: The above folder should be your rails project root folder.

Step 3: Click Security tab, click ADD, and type IIS_WPG, and then click OK.

Step 4: With IIS_WPG selected, click to select the following check boxes, and then click OK:

* Read and Execute
* List Folder Contents
* Read

Step 5: Open the Sharing and Security dialog box for the <yourrailsproject>\tmp folder, and then grant Full Control to the IIS_WPG group

Step 6: Close all the Sharing and Security dialogs, and restart IIS server.

Issue the following command in the Start->Run command window "iisreset"

Now, fire up your web browser (Firefox :)), and type http://localhost:81/test/about

You should be able to see the message from rails application as " Testing app v1.0 "

If for some reason if you are not able to see, then i suggest that you give Full Control in the Step 4.