I'm writing an ActiveX control using the firebreath framework (hi taxilian!) and while it technically works, I'm running into a weird issue that appears to be unique to me.

I've followed the instructions to create a simple plugin and then I ran it in Internet Explorer 8 on Windows 7 x64 (firebreath sets up a test page for the control). But as soon as I try to test it (clicking on a link that fires off JavaScript to interact with the control), IE crashes. Hard. "Internet Explorer has stopped working" style.

If I try the control in Firefox (the resulting registered DLL can also be called as a Firefox plugin using a MIME type), it works fine.

If I try it on my XP box, it works fine.

I emailed the DLL and the testing page to a coworker in the next cube who is like me also running Windows 7 x64 and it works for him just fine as well, so it's not something unique to Windows 7 or x64.

When it crashes I get this message:

Problem signature:
  Problem Event Name:   APPCRASH
  Application Name: iexplore.exe
  Application Version:  8.0.7600.16385
  Application Timestamp:    4a5bc69e
  Fault Module Name:    RPCRT4.dll
  Fault Module Version: 6.1.7600.16385
  Fault Module Timestamp:   4a5bdb3b
  Exception Code:   c0000005
  Exception Offset: 000220b1
  OS Version:   6.1.7600.2.0.0.256.1
  Locale ID:    1033
  Additional Information 1: 0a9e
  Additional Information 2: 0a9e372d3b4ad19135b953a78882e789
  Additional Information 3: 0a9e
  Additional Information 4: 0a9e372d3b4ad19135b953a78882e789

Which tells me nothing extremely useful. I can have it attach to a debugger but it just tells me a long list of DLL's, none of which are the ActiveX control in question. It's almost like it's not even getting there.

I did a sfc /scannow yesterday to see if anything on my system is corrupt and nothing came up as wrong. I tried various different security levels in IE, but nothing seems to have any effect.

As this is a development machine there has been all matter of crap installed on it, so I figure it's bound to be something I've installed since October (when Win7 was released) but I cannot figure out what it is. I presume the information it's giving me when I attach to Visual Studio is useful somehow but I don't know how to interpret it.

Admittedly I'm mainly a C#/.NET developer who's a bit out of his element with C/C++ and troubleshooting native code, but does anyone have any advice on how to proceed on figuring out why this very simple ActiveX control crashes IE on my machine and nowhere else?