In order for your SSI to work, the web page must have either .sht or .shtml extensions.

Sample SSI:

<!--#exec cgi="/cgi-bin/count.cgi"-->

Please note that the url must be relative as shown above. Following would not work:

<!--#exec.cgi="http://yourdomain.com/cgi-bin/count.cgi"-->

For more discussion on SSI, please click here.