El Capitan Mail Scripting, error -10000, -1708

Script “Mail Rule - Add attachments to DEVONthink Pro.scpt” works fine but I get an handler error for 1 Mail with 5 Attachments (see screenshot).

The reason is

... in mail attachments of ...


get name of mail attachments of theMessage


if (count mail attachments of theMessage) = 0 then

In the forum I have found a note that it could be a bug in Apple Mail (see [url]Yosemite Mail Scripting, error -10000]).

Exist a workaround / other coding for this problem ?
Screen Shot 2016-11-30.png

What kind of email account do you use (POP3, IMAP etc.)? Could you redirect a copy of the email to cgrunenberg - at - devon-technologies.com? Thanks!