Running programs - is there a depth limit. Also window waking

[LineCutter]

2 questions for the price of 1.

I've got a little program written that uses a separate exe for config. They share the same ini files. When the Prefs program sets HW.RunAppAtEvent(AppPath&"\MyApp.exe",HW.evWakeup) I can see MyApp.exe in the notifications queue... but when the device wakes it complains that it can't run it. The program is on an Sd card & 2 directories deep from there, could this be the problem (I can run MyApp fine by tapping it directly).

Second question: I need the MyApp.exe to leap into action without a pause. Loading the program & a couple of dlls is enough to get the waitcursor displayed. I'd like to flip the screen up from hiding, rather than closing it between uses. I can do that, & summon it back - from within the program. What I'd like is to be able to do that triggered by a hardware event & for something like dzHW.dll to be able to send a message that MyApp can act on to reset itself ready for the next run. I think that this involves some dark magic with window messages, but I can't see how to get these recognised within my B4PPC program.