Just bought FE: Legendary Heroes via Steam. Downloaded and installed it. On launch, I get an Application Error alert panel with the message:

The instruction at 0x770532a0 referenced memory at 0x04d86f9a. The memory could not be read. (CLick OK, Cancel, etc.)

This is running on a HP desktop with 8GB of RAM, running Win7 64bit Pro (SP1). 

The debug.err file in My Games/Legendary Heroes simply says:

DebugMessage: Version 1.20 last updated on: 07-19-2013 07:28
DebugMessage: Entering WinMain
Debug Message: Command Line:

I've made multiple attempts; sometimes, the splash screen will come up (in spite of the alert box, or even without it), but after that, the screen goes black (with the game cursor visible) and nothing more happens.   ..bruce..

7/21: solved the problem; did a manual download of the latest ATI Catalyst installation (the graphics card is a Radeon HD 6570), rebooted the system, and everything works just fine.