I would first see if the echo.bas program runs from the cgi-bin correctly.
I would then create a console mode test program to make sure MySQL is working for you. (without CGI / HTML code)
scriba -d your_pgm.bas will show you debug output for the extension module loading and tell you if it failed or not.
If everything looks good at this point and your still having problems running your script, repost your code so I can have a peek.
If your running under Windows, don't forget to change the first line.
# ! C:/scriptbasic/bin/scriba -c