I think the japi extension module was done by one of Peter Verhas's students long ago. I would like to see it work. If you need help with the SB extension module API, just post something here.
I have japi working.
installed SB_2.1_RC1_Linux.tar (needed the source files)
installed scriba-v2.1.1_i386.deb (over SB_2.1_RC1)
installed dependencies
installed graphics environment for command line, x11 xorg. (probably not needed for full installs, mine is a ubuntu server install, apache2 command line)
compiled japi source (lots of warnings, no errors)
copied the new japi.so to /usr/local/lib/scriba
copied the unix version japi.bas to /usr/share/scriba/include (made no changes)
Trying out the unix samples. Needing to increase command line font size is my biggest problem under x11. Any help with that would be appreciated.