Trap/script for arrow keys?

[Judy Perry]

I get this message for error description:

Error description: do: error in source expression

 b
" There was an Execution Error at 5:55:56 PM
Error description:  set: can't set property
Object: card id 1002 of stack "/TiX/Users/judyperry/Documents/RunRev
Stuff/MovingSprite.rev"
--------------------
switch tKey
--------------------
Value: arrowKey


" There was an Execution Error at 5:54:54 PM
Error description:  subtract: destination has a bad format (numeric?)
Object: card id 1002 of stack "/TiX/Users/judyperry/Documents/RunRev
Stuff/MovingSprite.rev"
--------------------
subtract 10 from theXcoord
--------------------

and

Error description:  Object: coordinate is not a point

Line: 0 Character: 0
Value: theXcoord

Error description:  Chunk: can't set property
set the loc of btn "Fish" to theXcoord,theYcoord
Line: 12 Character: 15
Value:

But the math aspect of it works just fine from within a button (the
business of adding or subtracting 10 from theX|Ycoord).

???

Judy