We recently installed Discoverer on a new XP machine. Windows Firewall is disabled and there are no additional firewalls installed on it. I even used the 3 .ORA config files from working desktops and have been testing this as an Administrator. I also saw that setting a environment variable "USE_SHARED_SOCKET=TRUE" might help and it hasn't. Here are some logs and results of a trace.

Fatal NI connect error 12203, connecting to:
(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=BEQ)(PROGRAM=oracle80)(ARGV0=oracle80ORCL)(ARGS='(DESC RIPTION=(LOCAL=YES)(ADDRESS=(PROT OCOL=beq)))')))(CONNECT_DATA=(SID=ORCL)(CID=(PROGRAM=C:\orant\jre11\bin\java.exe)(HOST=X225A)(USER=A dministrator))(SERVER=dedicated)) )

VERSION INFORMATION:
TNS for 32-bit Windows: Version 8.0.4.0.0 - Production
Oracle Bequeath NT Protocol Adapter for 32-bit Windows: Version 8.0.4.0.0 - Production
Time: 30-OCT-06 16:59:41
Tracing to file: C:\orant\NET80\LOG\oracle_trace.log.trc
Tns error struct:
nr err code: 12203
TNS-12203: TNS:unable to connect to destination
ns main err code: 12560
TNS-12560: TNSrotocol adapter error
ns secondary err code: 0
nt main err code: 530
TNS-00530: Protocol adapter error
nt secondary err code: 0
nt OS err code: 0


--- TRACE CONFIGURATION INFORMATION FOLLOWS --- New trace stream is "C:\orant\DISCVR31\trace.log.trc"
New trace level is 6
--- TRACE CONFIGURATION INFORMATION ENDS ---
nigini: entry
nigini: Count in NI global area now: 1
nigini: Count in NI global area now: 1
nrigbi: entry
nrigbni: entry
nrigbni: Unable to get data from navigation file tnsnav.ora
nrigbni: exit
nrigbi: exit
nigini: exit
niqname: Hst is already an NVstring.
niqname: Inserting CID.
niotns: entry
niotns: niotns: setting up interrupt handler...
niotns: Not trying to enable dead connection detection.
niotns: Calling address: (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=BEQ)(PROGRAM=oracle80)(ARGV0=oracle80ORCL)(ARGS='(DESC RIPTION=(LOCAL=YES)(ADDRESS=(PROT OCOL=beq)))')))(CONNECT_DATA=(SID=ORCL)(CID=(PROGRAM=C:\orant\jre11\bin\java.exe)(HOST=X225A)(USER=A dministrator))))
nricall: entry
nric2a: entry
nric2a: Getting local community information
nriglp: entry
nriglp: Looking for local addresses setup by nrigla
nriglp: No addresses in the preferred address list
nriglp: exit
nric2a: TNSNAV.ORA is not present. No local communities entry.
nrigla: entry
nrigla: Getting local address information
nrigla: Address list being processed.
nrigla: No community information so all addresses are local
nrigla: exit
nridst: entry
nridst: Resolving address to use to call destination or next hop
nridst: Processing address list.
nridst: No community entries so iterate over address list
nridst: exit
nric2a: This is a local community access
nric2a: exit
nricall: Got routable address information.
nricall: Making call with following address information: (DESCRIPTION=(CONNECT_DATA=(SID=ORCL)(CID=(PROGRAM=C:\orant\jre11\bin\java.exe)(HOST=X225A)(USER=Adm inistrator)))(ADDRESS=(PROTOCOL=B EQ)(PROGRAM=oracle80)(ARGV0=oracle80ORCL)(ARGS='(DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq)))')) ).
nricdt: entry
nricdt: Calling with outgoing connect data: (DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=BEQ)(PROGRAM=oracle80)(ARGV0=oracle80ORCL)(ARGS='(DESC RIPTION=(LOCAL=YES)(ADDRESS=(PROT OCOL=beq)))')))(CONNECT_DATA=(SID=ORCL)(CID=(PROGRAM=C:\orant\jre11\bin\java.exe)(HOST=X225A)(USER=A dministrator)))).
nscall: connecting...
nlpcaini: entry
nlpcaini: prg =
nlpcaini: arg[0] =
nlpcaini: arg[1] =
nlpcaini: exit
nsmal: 400 bytes at 0x95f910
nsmal: 1664 bytes at 0x2dd1818
nsopen: opening transport...
nserror: nsres: id=0, op=65, ns=12560, ns2=0; nt[0]=530, nt[1]=0, nt[2]=0
nsopen: unable to open transport
nsmfr: 1664 bytes at 0x2dd1818
nsmfr: 400 bytes at 0x95f910
nricdt: Call failed.
nricfg: entry
nricfg: exit
nricdt: Call made to destination.
nricdt: Processing address list so continuing.
nricdt: exit
nric2a: entry
nric2a: Getting local community information
nriglp: entry
nriglp: Looking for local addresses setup by nrigla
nriglp: No addresses in the preferred address list
nriglp: exit
nric2a: TNSNAV.ORA is not present. No local communities entry.
nrigla: entry
nrigla: Getting local address information
nrigla: Address list being processed.
nrigla: Processed all addresses in address list. Failed to make contact.
nrigla: exit
nric2a: exit
nricie: entry
nricie: Result descriptor: 12203,12560,530,0.
nricie: Result descriptor: 12203,12560,530,0 from Interchange:
nricie: exit
nricall: Exiting NRICALL with following termination result: -1.
nricall: exit
nioqper: error from nricall
nioqper: nr err code: 12203
nioqper: ns main err code: 12560
nioqper: ns (2) err code: 0
nioqper: nt main err code: 530
nioqper: nt (2) err code: 0
nioqper: nt OS err code: 0
niqme: entry
niqme: reporting nr (1) error: (12203) as rdbms err (12203)
niqme: exit
niotns: Couldn't connect, returning 12203
nigtrm: Count in the NI global area is now 0
nrigbd: entry
nrigbd: exit
nigtrm: Count in the NL global area is now 0