Not working under a MAMP set-up

Thank you for the great Postlet upload tool! In addition to the ImageX module, I've been able to integrate it into one custom module and I am planning to build it into yet another.

I am currently modifying my development workflow to include coding and testing on a local web server -- using the MAMP set-up under Mac OS X (as is recommended within the Drupal documentation and forums). I discovered that file uploads through Postlet don't get converted into nodes under this server set-up. (Works fine on my Linux based hosting accounts).

MAMP uses the following path for the Temp Directory (configured in the php.ini):
upload_tmp_dir = /Applications/MAMP/tmp/php

I'm curious as to whether Postlet is hard coded to place the uploaded files somewhere else? That would cause the php-based receiver function to not find the uploaded files for post processsing. Is there a way to tell Postlet where to place the uploaded files?

(Note: HTTP Post of the same test image file does succeed. ImageX / Postlet upload reports 'complete' but does not produce an Image node. In fact, I have not been able to find where the uploaded file has been placed in the file system.)

If the upload Temporary Directory is not a likely cause of the problem, maybe you have suggestions on other things I should check?

Thanks in advance for any advice you can provide as I attempt to troubleshoot this issue.