[Zope] ZOracle problems

I've installed DCOracle in a Zope instance running with PCGI + Apache variation; Zope process is running with the same user the web server is running; DCOracle test was fine (I also created a small Python app to access a test database); The .so files were copied to the right place. But when I try to connect to the database (or create a connection and test it in the same operation) it gives an Apache error: "Internal Server Error The server encountered an internal error or misconfiguration and was unable to complete your request."... Verifying the error_log file, this is what I've found: PCGI Error: [503 Service Unavailable] ((116) unable to connect, fd=4) Success What could be happening? Thanks for any help. Alexandre.