nsswitch.conf is a list of the rules to use in translating a name into an IP address. The default one is often not useful. Typically, you want to look in /etc/hosts first, then if not resolved, ask a DNS server. Your startup scripts are failing because they depend on network resources.
It is important to understand what the script is doing so you can troubleshoot the real problem. By removing nsswitch.conf, all addresses will be resolved by your DNS server(s) listed in /etc/resolv.conf, or if none exists, by looking in /etc/hosts. Xmanager also needs network resources, specifically your hostname. If your DNS servers have the wrong IP for your server, then Xwindows will have problems.
You can't determine anything about the problem until you trace the SAP start/stop script. You'll need to see the errors that cause the startdb not to be called. It may be that startdb is actually being called but is reporting an error in the SAP logs. Have you looked at the start/stop log /etc/rc.log?
Bill Hassell, sysadmin
