Copying email content with AppleScript

Question

I'm hoping someone out there can tell me what's going on here...
I'm trying to extract text from an email using an AppleScript.  The script is being called by a mail rule based on a particular sender.  The script I have cobbled together from a few online sources is:
tell application "Finder" to set ptd to "Macintosh HD:Users:Rob:Documents:Rob Woods Art:Vitec:Tasks:" as string
using terms from application "Mail"
          on perform mail action with messages theIncomingMessages for rule theRule
                    tell application "Mail"
                              repeat with each_message in theIncomingMessages
                                        set theText to content of theIncomingMessages
                                        set theFile to ptd & "Task " & (theIncomingMessages's id as string)
                                        set theFileID to open for access file theFile with write permission
  write theText to theFileID
  close access theFileID
                              end repeat
                    end tell
          end perform mail action with messages
end using terms from
What should happen is I get a text file at the location defined at 'ptd' called 'Task (id)'.  But I get nothing.  I know the rule is running OK as it also plays a sound only on that rule.
I'm banging my head now!  I'm running Snow Leopard if it makes any difference.
Thanks peeps.
Rob

Answer 1

In case it helps debug this, I've been messing around and with the message selected, if I apply rules from the menu, I get what I expected - a txt file with the content written out.  But it's only working because I have the message selected. 
Does that ring any bells?
Rob