Hi Peter: 
Before post this msg I read many msg of this forum. Then I did a lot of thinks before try install FSUIPC4: 
I unisntalled and installed FSX 
I installed SP1 
I started several times FSX 
I saved missions  
Finally, I tried a lot of thinks before but the result was always the msg bellow. 
Then what could I do to install it? I use Windows XP and Norton Internet Security. My computer is top; no hardware problem. 
Thanks in advance for your answer 
Installer for FSUIPC4.DLL version 4.20 
Looking in registry for FSX install path: 
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Games\Flight Simulator\10.0 
Parameter"SetupPath" 
SetupPath="H:\Arquivos de programas\Microsoft Games\Microsoft Flight Simulator X\" 
Checking version of FSX.EXE: 
... Version 10.0.61355.0 (Need at least 10.0.60905.0) 
Checking compatibility with installed SimConnect: 
... Probe Manifest fails to match a valid base SimConnect needed to load FSUIPC4! 
Found later build SimConnect 61242 (SP1 May07)