A few things to check.
Make sure your home directory in the config points to your app-bin directory. You are regenerating the binary format of the config with each change, correct? You are restarting sbhttpd each time you change the config, correct?
Keep in mind that sbhttpd doesn't process anything but Basic programs so images need to be served up by Apache.
Try a "Hello World" like CGI program first and then move on to echo.bas and beyond.
You could try running your echo.bas with scriba as a standard CGI script. (make sure it is in a executable cgi-bin directory in this case)
As an option, I offer setup and support services (fee based) if working through this on your own is getting frustrating. I remember my first time getting sbhttpd going and drove Peter Verhas nuts.
