I was contacted by a customer who commented that he could not add a Script Map to IIS 5.1. After selecting his executable for the script map and adding his extension, the “OK” button was still disabled — preventing him from committing the script map change.
To work around this issue, once you have selected the executable and set the extension, click inside the “Executable” text box to expand the full path to the executable. Doing so will enable the OK button and you will be able to commit your script map change.