Usually the windows Nt error message is triggered by attempting to run EAW from an exe that is called someting other than eaw.exe. Look at you main directory and see what the exe is called. If it is different than EAW.exe save a copy and change the on in the eaw folder to EAW.exe, then try it again.
Also, it is best to just copy the EAW cd into a new folder rather than installing it. Once you have copied it run it and start a career, start a misson then exit the program. The sim should run fine. If it does, then do the upgrades. If your Briefing Screen is messed up, that is a problem being sorted out currently by those working on 1.28C etc.