My Win XP and Win 7 computers did not appear in windows explorer under networks.
I had the same issue as you with "Net View" and message "System Error 6118 has occurred".
I have searched a lot and applied a lot of advices found on the net.
Finally, I found the explanation for my configuration ( not sure that config of other persons is the same).

The main advice I can give to everyone : look in the eventviewer ( "administrative events" ).
This will spare you a lot of time !!
The reason was :
a PRINTER was blocking the computers from being master browser.
Message in eventviewer was "The name "WORKGROUP      :1d" could not be registered on the interface with IP address 192.168.1.13. The computer with the IP address 192.168.1.5 did not allow the name to be claimed by this computer."
Solution I applied (perhaps there are other solutions) : I set the printer to let it get its ip address from the dhcp ( ip dynamic address in place of static address ).  Another solution is probably to use another workgroup name than "workgroup".

RHEL 6.5 rhn_register error

ERROR :


  File "/usr/sbin/rhn_register", line 76, in <module>
    app.run()
  File "/usr/share/rhn/up2date_client/rhncli.py", line 84, in run
    sys.exit(self.main() or 0)
  File "/usr/sbin/rhn_register", line 58, in main
    ui.main()
  File "/usr/share/rhn/up2date_client/tui.py", line 1278, in main
    tui.run()
  File "/usr/share/rhn/up2date_client/tui.py", line 1226, in run
    win = self.windows[index](self.screen, self)
  File "/usr/share/rhn/up2date_client/tui.py", line 460, in __init__
    hw_activation_code = rhnreg._activate_hardware(self.tui.userName, self.tui.password)
  File "/usr/share/rhn/up2date_client/rhnreg.py", line 650, in _activate_hardware
    login, password, hardwareInfo)
  File "/usr/share/rhn/up2date_client/rhnreg.py", line 681, in activateHardwareInfo
    hardwareInfo, other)
  File "/usr/share/rhn/up2date_client/rhnserver.py", line 53, in __call__
    raise self.__exception_from_fault(f)
<class 'up2date_client.up2dateErrors.AuthenticationOrAccountCreationError'>: Error validating data at server:
Error Message:
    Invalid username/password combination
Error Class Code: 2
Error Class Info:
     Invalid username and password combination.
     If you are using email address as a login, try using your associated
     login name instead.
Explanation:
     An error has occurred while processing your request. If this problem
     persists please enter a bug report at bugzilla.redhat.com.
     If you choose to submit the bug report, please be sure to include
     details of what you were trying to do when this error occurred and
     details on how to reproduce this problem.




RESOLUTION


register from command line
#subscription-manager register --name systemname --consumerid=afbefc25-f26f-XXZ3-af1b-76a52332hGb4f7af --autosubscribe