That's so it knows that I'm talking about an Appvar

oh wait -- I remember know how that works. But why the _E?

EDIT: also, look at this:
GetCalc(Str1,0)->Q
why would you want an appvar that is zero bytes large?

_E allows you to store a number using hexadecimal notation.
Just like pi allows you to store a number using binary notation.

RE: 0 Byte Appvar:

So it wasn't crashing, it just did nothing?

Copy(P,V+W,length(P))

are you sure you want to be using P here, not L1 or the pointer to L1? Because P is just a string of tokens.

Also, I'm confused here:

If B

because B is never defined, ever, in your code so far (as far as I can tell)

Here's a good debugging technique: comment out everything but the first line. Then compile and run the code. If it doesn't crash, that line is not the problem line. Then, go back into the source and un-comment the second line (if the second line is some kind of If statement or something like that that requires an 'End', un-comment as much as you have to for the control structure to be valid). Compile and run the code. If it doesn't crash, whatever you just un-commented is not the problem. Et cetera et cetera repeat ad infinitum forever and ever worlds without end, amen. Once you have it narrowed down to one line that's causing the problem, it's easy to fix.

Let me know if that works