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.
For a manual install this would work, although you'd probably still have to link it into the various /etc/rcX.d/... either by hand or using update-rc.d. For anything newer than lenny, the program is available as a package which includes an init script already.