The best way to solve any service start up errors in Linux is to run them manually with debug mode on. The difficulty comes from finding exact command line arguments to be passed (as if it were started by Linux start up scripts) and also disabling default daemon mode for the server command. You can easily find the options to enable debug mode for the server by quickly looking at man page.

For example, you can use following command to run xinetd service in the foreground with debug on.

[root@techpulp ~]# /usr/sbin/xinetd -d -dontfork
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/chargen-dgram [file=/etc/xinetd.conf] [line=49]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/chargen-stream [file=/etc/xinetd.d/chargen-stream] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/cvs [file=/etc/xinetd.d/cvs] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/daytime-dgram [file=/etc/xinetd.d/daytime-dgram] [line=19]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/daytime-stream [file=/etc/xinetd.d/daytime-stream] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/discard-dgram [file=/etc/xinetd.d/discard-dgram] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/discard-stream [file=/etc/xinetd.d/discard-stream] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/echo-dgram [file=/etc/xinetd.d/echo-dgram] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/echo-stream [file=/etc/xinetd.d/echo-stream] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/rsync [file=/etc/xinetd.d/rsync] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/tcpmux-server [file=/etc/xinetd.d/tcpmux-server] [line=14]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/tftp [file=/etc/xinetd.d/tftp] [line=68]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/time-dgram [file=/etc/xinetd.d/time-dgram] [line=19]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/time-stream [file=/etc/xinetd.d/time-stream] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {handle_includedir} Reading included configuration file: /etc/xinetd.d/vmware-authd [file=/etc/xinetd.d/vmware-authd] [line=67]
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing chargen
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing chargen
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing cvspserver
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing daytime
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing daytime
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing discard
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing discard
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing echo
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing echo
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing rsync
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing tcpmux
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing tftp
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing time
10/4/13@00:34:14: DEBUG: 3657 {remove_disabled_services} removing time
Service defaults
Instances = 50
Groups = yes
umask = 2
CPS = max conn:50 wait:10
PER_SOURCE = 10
Bind = All addresses.
Only from: All sites
No access: No blocked sites
Logging to syslog. Facility = daemon, level = info
Log_on_success flags = HOST DURATION EXIT PID
Log_on_failure flags = HOST

Service configuration: vmware-authd
id = vmware-authd
flags = IPv6
type = UNLISTED
socket_type = stream
Protocol (name,number) = (tcp,6)
port = 904
wait = no
user = 0
Groups = yes
umask = 2
PER_SOURCE = 10
Bind = All addresses.
Server = /usr/sbin/vmware-authd
Server argv = vmware-authd
Only from: All sites
No access: No blocked sites
Logging to syslog. Facility = daemon, level = info
Log_on_success flags = HOST DURATION EXIT PID
Log_on_failure flags = HOST

10/4/13@00:34:14: DEBUG: 3657 {cnf_start_services} Started service: vmware-authd
10/4/13@00:34:14: DEBUG: 3657 {cnf_start_services} mask_max = 6, services_started = 1
10/4/13@00:34:14: NOTICE: 3657 {main} xinetd Version 2.3.14 started with libwrap loadavg labeled-networking options compiled in.
10/4/13@00:34:14: NOTICE: 3657 {main} Started working: 1 available service
10/4/13@00:34:14: DEBUG: 3657 {main_loop} active_services = 1
^C10/4/13@00:34:15: NOTICE: 3657 {general_handler} Unexpected signal 2 (Interrupt)
[root@techpulp ~]#

In the above case, I have pressed Ctrl+C to stop the process. However if you have a problem of starting xinetd service on your system, you should see some relevant error before process exits.