FC5 Updatihng FC4 - Network Problem

[John Ackley]

two workstations, both running FC4 - in use for some time - no problems
one updated to FC5 - no problems
second updated but does not connect to network
otherwise acts normal

command "service network start" - reports "OK" - no error messages
"tcpdump" shows activity on network from other boxes
"netstat -nr" shows normal ip, gateway etc.
"ifconfig -a" shows normal parameters
ping to self works ok
ping to remote - "No route to host"
ping from remote - "No route to host"

then I try to turn off firewall with
system-config-securitylevel
returns error: "IndexError: list index out of range" line 371 of 
selinuxPage.py
(traceback 371,379,402 in securitylevel.py,240 in securitylevel.py)

where do I look next?
TIA