The plot thickens. As I continue to try to work through this problem in an effort to learn something, I find this peculiarity. If I copy the script that is generating the error from a sub-folder of my Zope instance to the root folder, rather than a Zope error, I get a file download dialog indicating I am trying to download a file of type application/x-httpd-cgi. The external method this script is calling is stored at the root level of the Zope instance. So here's the script that's causing the problem: for image in context.objectValues('Image'): if not image.hasProperty('original_id'): context.makeThumbnail(image.getId()) the makeThumbnail script it's calling is an external defined at the root level. It works fine when run from a URL against a single image whose ID is provided as an argument (as described on pp. 156-157 of the Zope Book). But if I attempt to call it from this for-in loop in a non-external Python script, I get these weird conditions. Mysteriouser and mysteriouser. -- Dan Shafer, Personal Creativity Trainer and Consultant Trained Hartman Value Profile Analyst http://www.danshafer.com/valueprofile.html