Self-posted solution: The issue here was that the EPW file had a typo: January 1 for 2008, which was the appropriate year for the AMY file, was a Tuesday. The EPW file listed Tuesday as "Tuesdayy" with two y's. The solution was to simply delete one of the extra y's, save the file, rezip the file, reupload to dropbox, and recreate the direct download link to post into Worker initialization Script field.

EPW file before edit:

EPW file after edit: