[horde] PGP: PHP Fatal error when sending Mail with attachment

[Andreas Mauser]

Hi,

I trust you all had a merry xmas!

When sending a mail w/o attachment I find no problems encrypting mails  
in Horde.

Sending an attachment did not work and put this error message in the  
error.log:

[Tue Dec 30 09:38:10.964678 2014] [:error] [pid 23114] [client  
192.168.24.101:46515] PHP Fatal error:  Call to a member function  
setTransferEncoding() on a non-object in  
/usr/share/pear/Horde/Crypt/Pgp.php on line 1258, referer:  
https://mauser.info/mailoffice/imp/dynamic.php?page=compose&buid=8179&mailbox=SU5CT1g&type=reply&token=Ev8Qy0xF8fva8EAgifsLnQ2&uniq=1419927204699

Is this something easy to fix, or did I a user mistake?
I tried to send a png and a txt within the mail I tried to encrypt with horde.

Thank you,
Andreas
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-keys
Size: 3871 bytes
Desc: ��ffentlicher PGP-Schl��ssel
URL: <http://lists.horde.org/archives/horde/attachments/20141230/a2bd02ad/attachment.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 819 bytes
Desc: Digitale PGP-Signatur
URL: <http://lists.horde.org/archives/horde/attachments/20141230/a2bd02ad/attachment-0001.bin>