Second Remote desktop session issue

I was able to use remote desktop to remote control a office XP
workstation(XP_B). Thru that office workstation, I run a remote desktop
session on XP_B to remote control server 2003. Within these recent few
months, I found it can't work. (XP_B can't remote server_C now)

XP_A -- remote control ---> XP_B (XP with SP3, latest windows update)
-----X-remote control -X----> server_C (W2k3 with SP2, latest windows update).

Would anyon have idea how to fix it, please ?

Event log on XP_B:
Event Type: Error
Event Source: Application Hang
Event Category: (101)
Event ID: 1002
Date: 6/1/2009
Time: 9:01:19 AM
User: N/A
Computer: XP_B
Description:
Hanging application mstsc.exe, version 6.0.6001.18000, hang module hungapp,
version 0.0.0.0, hang address 0x00000000.

For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 41 70 70 6c 69 63 61 74 Applicat
0008: 69 6f 6e 20 48 61 6e 67 ion Hang
0010: 20 20 6d 73 74 73 63 2e mstsc.
0018: 65 78 65 20 36 2e 30 2e exe 6.0.
0020: 36 30 30 31 2e 31 38 30 6001.180
0028: 30 30 20 69 6e 20 68 75 00 in hu
0030: 6e 67 61 70 70 20 30 2e ngapp 0.
0038: 30 2e 30 2e 30 20 61 74 0.0.0 at
0040: 20 6f 66 66 73 65 74 20 offset
0048: 30 30 30 30 30 30 30 30 00000000

Server_C does not capture success / fail login session on event log.