SYMPTOM:
An ESRI Map configured with custom areas in Strategy Web 9.4.1 HF3 might show the following error when executing the document in flash mode or the Visual Insight Dashboard:
"Custom Shapes IOError. Error reading the resource $FileName"

There are several reasons for this error to occur, however, a fiddler trace of the execution will reveal an HTTP 404 Error as shown below:
The Fiddler Web View for the response will show that the exact error message is an HTTP 404.3 error corresponding to a MIME type configuration as illustrated below:

CAUSE:
Keyhole Mark Up Language (KML) files are not pre-configured as allowed MIME types in Microsoft IIS. If the Strategy Web 9.4.1 HF3 administrator wants to enable the custom shape functionality for ESRI then the MIME type for KML has to be enabled by the Web Server Administrator.
ACTION:
To enable KML files as an allowed MIME type to be served by Microsoft IIS 7.0 follow these steps:


File Name extension: .kml MIME type: application/vnd.google-earth.kml+xml

Important Note: J2EE servers normally come with KML files pre-configured, if this problem is encountered in any other server brand contact the appropriate Web Server administrator.
KB47283