An unknown error (-17199) occurred. (Is there a property so this doesn't display?)

[gimme_this_gimme_that]

Entourage says:

"A message in your Outbox could not be sent. The account which created
the message cannot be found."

I'm sending the message from Script Editor with this script:

tell application "Microsoft Entourage"
activate
set filePath to "Macintosh HD:Users:annocuments:igawk.1.pdf"
set smtp_account to IMAP account "ann_example"
set msg to make new outgoing message with properties {subject:"Gwak
Documentation", content:"Here it is", recipient:"Ann Example
<[email protected]>", attachment:alias filePath,
account:smtp_account}
send msg
end tell

The error is benign, the message gets sent.

But is there a property that can be set so this error message does not
display?


Thanks.