[imp] Could't strip attachment in message view (Horde 4.1.1+IMP 4.1)

[David Chang]

While click "strip attachment" icon in message view,i got this error message:
Mar 30 16:30:24 HORDE [debug] [imp] An error occured while attempting  
to strip t
he attachment. The IMAP server said: Message contains invalid header  
[on line 15
8 of "/usr/local/apache/horde/lib/Horde/Notification.php"]

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ENV: Horde 4.1.1 + IMP H3 4.1 ,and Cyrus IMAP4 v2.1.18
test.php can find here : https://210.241.49.68/horde/test.php

Is this bug ,or something i missed ?

David Chang