snapshot and animation capture

[Richmond]

So, I thought I'd have a bash at rolling my own, but got stuck:

on mouseUp
    put topleft of img "border.png" & "," & the bottomright of img 
"border.png" into ZZZZ
    put quote & ZZZZ & quote into fld "guff"
    put fld "guff" into QQQQ
    export snapshot from rect QQQQ of stack "Super Snap" to file 
"QQQQ.png" as PNG
end mouseUp

the thing gets stuck on the "export snapshot" line . . . cannot think 
why . . .

image "snapBTN.png": execution error at line 5 (import: error in 
expression), char 1

that stuff about "char 1" makes NO sense at all.

Richmond.