I have the same problem. I was using the J41 just fine with no issues and took about a month off from FSX. After a month, when I try to load the J41, I get a CTD. I tried uninstalling it and reinstalling it and I still get the same error. It doesn't matter if I load it from the opening screen or if I load it after loading a default aircraft. I have Windows 7 with all updates.
Matt
The event viewer says the following:
Faulting application name: fsx.exe, version: 10.0.61637.0, time stamp: 0x46fadb14
Faulting module name: KERNELBASE.dll, version: 6.1.7601.18229, time stamp: 0x51fb1116
Exception code: 0xe06d7363
Fault offset: 0x0000c41f
Faulting process id: 0x1f98
Faulting application start time: 0x01cf22cff2689985
Faulting application path: D:\FSX\fsx.exe
Faulting module path: C:\Windows\syswow64\KERNELBASE.dll