Pete, 
We've got an issue with setting weather via the New Weather Interface (NWI) in Microsoft FlightSim 2004 (COF). 
When weather is set via NWI & FSUIPC the flightsim crashes within a few minutes. 
Our setup consists of; 
1 pc running MSFS+fsuipc+WideServer 
5 pcs running WideClient and the Glass Cockpit (2), the CDU (2) and the EICAS 
1 pc running WideClient and our software to control/interface with MSFS and ProjectMagenta 
All WideClient versions are 6.470 
The WideServer version is 6.47 
The FSUIPC version is 3.48 
All machines run WindowsXP. 
In the WideServer logfile I sometimes see this message. (The length is not always 25) 
	334907 **** ERROR! Sumcheck or length fails on received socket 2388 block, len=25 (time=22831891) 
In the FSUIPC logfile I sometimes see this message. 
	20969563 NW_SETEXACT weather command received, ICAO=GLOB  
	20969735 >NewSet:  **** New Weather [4] being set: ICAO=GLOB (Dyn=0) 
	20969735 >NewSet:  Pressure=1013.0, Drift=0.0 (Target=1013.0) 
	20969735 >NewSet:  Visibility: range=1.0sm (1609m) (Target=1.0sm), from=0ft, to=82021ft 
	20969735 >NewSet:  Cloud[0]: type=3, from 0ft to 19685ft (+/- 66ft), cover=7, turb=3, topshape=0 
	20969735 >NewSet:                      Precip=2, base=66ft, rate=4, icing=4 
	20969735 >NewSet:  **** End of New Weather details for ICAO=GLOB 
	20969797 ***ERROR C0000005 at 2112C218 ChainedProcFF (Diag=04000000) 
	20969797 ***      Access violation trying to read address 0000000C 
	20969797 ***      EAX 00000000  EBX 00000001  ECX 0D8D18F0  EDX 0117D418  EDI 0CA55A28  ESI 0CC692E8 
	20969797 Stack -1 (0920CC20) = 0042CB71, Bad=N 
	20969797 Stack -2 (19840110) = 00000003, Bad=Y 
	20969797 Stack -3 (4B434F43) = 20544950, Bad=Y 
	20975485  Results: FS98 Wind0: ground (-3ft) to 0ft AGL, dir 0M, vel 0, gust 0, turb 0 
	20990250  Results: FS98 Wind0: ground (0ft) to 0ft AGL, dir 0M, vel 0, gust 0, turb 0 
Please note that the log entries mentioned above dont occur with every crash, sometimes I get only one, sometimes none, sometimes both. Also note that the WideServer logfile and FSUIPC logfile from which these logs are taken are not from the same MSFS run. 
If you need more information I'd be happy to supply that... (I could mail some code snippets if that is useful). 
I hope you can help us with this, because we are out of options. 
sincerely, 
E van Nooijen. 
PS. Setting weather via the (advanced) weather interface within MSFS works fine.