I'm having trouble getting the DTCPing and DTCTester tools working between a WindowsXPsp3 machine and a Windows Server 2003 machine.

When I start DTCPing it's giving the error:
DTCping log file: c:\temp\COMPUTER1096.log
Error(0x57) at rpcUtil.cpp @133
-->I_RpcServerAllocateIpPort
-->87(The parameter is incorrect.)
Error(0x57) at rpcUtil.cpp @54
-->87(The parameter is incorrect.)
After restarting the msdtc service, a few errors and warnings appear in the Event Viewer:
Code:
Event Type:	Warning
Event Source:	MSDTC
Event Category:	Printers 
Event ID:	4358
Date:		29/10/2008
Time:		3:45:03 PM
User:		N/A
Computer:	COMPUTER
Description:
The MS DTC Connection Manager is unable to register with RPC to use TCP/IP or UDP/IP.  Please ensure that RPC is configured properly.  Error Specifics:d:\xpsp\com\com1x\dtc\dtc\cm\src\iomgrsrv.cpp:1911, Pid: 3220
No Callstack,
 CmdLine: C:\WINDOWS\system32\msdtc.exe

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Code:
Event Type:	Error
Event Source:	MSDTC
Event Category:	Printers 
Event ID:	4156
Date:		29/10/2008
Time:		3:45:03 PM
User:		N/A
Computer:	COMPUTER
Description:
String message: RPC raised an exception with a return code RPC_S_INVALIDA_ARG..

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.