I've just installed XAMPP + V4RB in clean environment on OS X 10.11 and get my Xojo Web app working in CGI mode without any problem:
1) Copied my files into cgi-bin folder:
/Application/XAMPP/xamppfiles/cgi-bin/
* test_cgi_local - it's an application folder
* Reports - folder which contains vsp file
2)
Important to change permissions, because in CGI mode web applications are started by apache.
Currently XAMPP runs apache as "daemon" user.
Execute these commands from Terminal.app to change permissions:
sudo chown -R daemon:staff Reports test_cgi_local
sudo chmod -R 755 Reports test_cgi_local
For testing (or if you don't know the user, etc) you can just allow everything to everyone on that folders:
sudo chmod -R 777 Reports test_cgi_local
3) Pointed browser to localhost/cgi-bin/test_cgi_local/testcgilocal.cgi
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So my question is - what error do you get and where do you see it?
In a case of an uncaught exception Xojo shows call stack right in the browser, so it is clearly visible, which method caused an error.