Do you experience problems during downloading?
Check your connection in Status and Interface settings window.
Use Test Server in Config > Servers.
We will probably ask you to do a test using only basic settings.
Do you experience problems during repair or unpacking?
Enable +Debug logging in the Status and Interface settings window and share the relevant parts of the log here using [ code ] sections.
I run sabnzbd behind apache, and I noticed that during the Wizard setup, the "Test Server" button didn't work. The call to tapi was uing a absolute path, not a relative one.