GIMP :: Unbound Variable Error With No Variable?

I'm attempting to write a batch script to add some layers to a pre-existing image and save a copy. I've gone through the tutorial, and have run the demo code from Basic_Batch with no errors, but my (what I think of as simple) script throws an "Error: eval: unbound variable: ?" It also seems to cascade the error to other scripts, as I then get "unmatched parentheses: 2" errors from what I assume to be the script immediately following my own during Script-Fu load. This occurs whether running from batch or clicking "Refresh Scripts" from the Script-Fu menu.

What I could find on this forum and Google suggests that I may be required to 'define' one or more of my variables before using it, but for the life of me, I can't figure out which one that would be, and the error (reporting that '?' is undefined!?) I've quintuply (probably more ~_^) checked my parenthesis matching, but they look fine to me.

In case this was an encoding issue, I've tried saving my .scm file as both UTF-8 and ANSI. I should also note that I'm running Windows 7 x64 in English-US.

Script:

(define (script-fu-build-imagebasefilemytext)(let*((image (car (gimp-file-load RUN-NONINTERACTIVE basefile basefile)))(drawable (car (gimp-image-get-active-layer image)))(title (car (gimp-text-layer-new image mytext "Courier" 18 UNIT-POINT))))(gimp-image-add-layer image title -1)(gimp-image-clean-all image)(gimp-file-save RUN-NONINTERACTIVE image drawable "K:\\Images\\Temp.gif" "Temp.gif")));

Since I intend for this script to only be run from batch, I haven't bothered including the typical register stuff.