Aperture Script - Can't replicate user problem

[adayzdone]

I wrote this script to Rename and File Aperture Projects by Date :
http://www.johneday.com/9/rename-and-file-aperture-projects-by-date

A Mountain Lion user has given me this feedback:

OK, so I get the error that the EXIF tag does not have capture year. I’m on Mountain Lion, and recall that it worked on one project the very first time I ran the script after downloading and installing it… it’s almost as if some flag gets set to true or false and it needs to be reset.

Can anyone running Mountain Lion replicate this problem for me? Any insights about what is going wrong for him would be appreciated.

(I enclosed the script in a try block in an attempt to find out what his issue was)

set yourFolder to "Imported by Date" -- Name your folder here
set appendParent to false -- If true, the selected parent's name will be appended to the new project name 
set makeSubfolders to false -- If true, new projects will be created in year/month/ folders.
property delimiter : "-"

try
	tell application "Aperture"
		activate
		
		-- Wait until Aperture is finished processing other tasks
		repeat
			set taskCount to count of tasks
			if taskCount is 1 then
				display alert "Aperture is processing another task" message "Please wait for the task to complete and try again" buttons {"Try again", "Cancel"} default button {"Try again"} cancel button {"Cancel"}
			else if taskCount > 1 then
				display alert "Aperture is processing " & taskCount & " tasks" message "Please wait for the tasks to complete and try again" buttons {"Try again", "Cancel"} default button {"Try again"} cancel button {"Cancel"}
			else
				exit repeat
			end if
		end repeat
		
		-- Verify that at least one item is selected
		if selection is {} then display alert "The selection {} is empty" message "Please select ONE Project, Folder or Album from the Library tab in the sidebar and try again." buttons {"OK"} cancel button {"OK"}
		
		-- Get the selected Parent ID
		tell item 1 of (selection as list) to set theParent to parent
		set {parentClass, parentName} to {class, name} of theParent
		if parentClass is album then display dialog "Albums may contain images from multiple projects. Are you sure you want to move these images from their projects?"
		
		-- Get date of every image in the selected Parent
		tell theParent to set dateList to every image version's (value of EXIF tag "ImageDate")
		
		tell library 1
			-- Create your folder if it does not exist
			if not (exists folder yourFolder) then make new folder with properties {name:yourFolder}
			
			-- Assign name of every project in your folder to a list for the Create project command below
			-- (exists project isoImageDate) command is too slow to be included in the loop
			if not makeSubfolders then tell folder yourFolder to set parentList to name of every project
			
			set dateTest to {}
			repeat with aDate in my dateList
				-- Test each date to avoid processing duplicates
				set shortDate to short date string of aDate
				if dateTest does not contain shortDate then
					set end of dateTest to shortDate
					
					-- Convert the image date to YYYY-MM-DD format 
					set projectYear to year of aDate as string
					set projectMonth to (month of aDate as integer) as string
					if length of projectMonth is 1 then set projectMonth to "0" & projectMonth
					set projectDay to (day of aDate as integer) as string
					if length of projectDay is 1 then set projectDay to "0" & projectDay
					set isoImageDate to projectYear & delimiter & projectMonth & delimiter & projectDay as string
					if appendParent then set isoImageDate to isoImageDate & space & parentName
					
					tell folder yourFolder
						if makeSubfolders then
							--Create year and month folders if year folder does not exist
							if not (exists folder projectYear) then make new folder with properties {name:projectYear}
							tell folder projectYear
								if not (exists folder projectMonth) then make new folder with properties {name:projectMonth}
							end tell
							--Create project if it does not exist
							if ((name of every project of folder projectMonth of folder projectYear) does not contain isoImageDate) then tell folder projectMonth of folder projectYear to make new project with properties {name:isoImageDate}
							
							-- Move the images into the project
							move (every image version of theParent whose value of EXIF tag "CaptureYear" is year of aDate and value of EXIF tag "CaptureMonthOfYear" is month of aDate as integer and value of EXIF tag "CaptureDayOfMonth" is day of aDate) to project isoImageDate of folder projectMonth of folder projectYear
							
						else -- If not makeSubfolders
							--Create project if it does not exist
							if parentList does not contain isoImageDate then make new project with properties {name:isoImageDate}
							
							-- Move the images into the project
							move (every image version of theParent whose value of EXIF tag "CaptureYear" is year of aDate and value of EXIF tag "CaptureMonthOfYear" is month of aDate as integer and value of EXIF tag "CaptureDayOfMonth" is day of aDate) to project isoImageDate
						end if
					end tell
				end if
			end repeat
			
			-- Move the initial container to the Trash if no images remain or if it is an album			
			if parentClass is album then
				delete theParent
			else if (count of image versions of theParent) is 0 then
				delete theParent
			end if
			beep
		end tell
	end tell
	
on error errMsg number errNum
	tell me
		activate
		display alert errMsg & return & return & "Error number" & errNum buttons "Cancel"
	end tell
end try

EXIF Tag Name Mapping:
The following table provides a mapping between EXIF tag names found in the Aperture 3 interface and EXIF tag names that appear in AppleScript.