[horde] Trouble with IMP 4.3.4 and S/MIME encrypted messages

[Bill Day]

Upon receiving and attempting to open an S/MIME encrypted email message, my
browser attempts to download "message.php" rather than decrypting and
opening the mail message. Signed messages do not seem to pose any problem;
they are properly verified.

My horde.log does not show anything other than login attempts.  An excerpt
from my apache access.log is quoted below.

Any suggestions for further troubleshooting or solutions would be much
appreciated.

Thanks,

Bill Day

71.241.253.30 - billday [26/Jul/2009:14:53:35 -0400] "POST
/horde/imp/smime.php?actionID=process_passphrase_dialog HTTP/1.1" 200 166 "
https://williamsonday.org/horde/imp/smime.php?actionID=process_passphrase_dialog"
"Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.12) Gecko/2009070811
Ubuntu/9.04 (jaunty) Firefox/3.0.12"
71.241.253.30 - billday [26/Jul/2009:14:54:05 -0400] "GET
/horde/imp/smime.php?actionID=open_passphrase_dialog&reload=7cf51ee33d8eb61c24d3b609bef75fad&uniq=1248634444825
HTTP/1.1" 200 92 "
https://williamsonday.org/horde/imp/message.php?mailbox=INBOX&index=7006"
"Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.12) Gecko/2009070811
Ubuntu/9.04 (jaunty) Firefox/3.0.12"
71.241.253.30 - billday [26/Jul/2009:14:54:46 -0400] "GET
/horde/imp/message.php HTTP/1.1" 200 5503 "-" "Mozilla/5.0 (X11; U; Linux
i686; en-US; rv:1.9.0.12) Gecko/2009070811 Ubuntu/9.04 (jaunty)
Firefox/3.0.12"
71.241.253.30 - - [26/Jul/2009:14:55:18 -0400] "GET
/horde/services/portal/sidebar.php?httpclient=1 HTTP/1.1" 200 2687 "
https://williamsonday.org/horde/services/portal/sidebar.php" "Mozilla/5.0
(X11; U; Linux i686; en-US; rv:1.9.0.11) Gecko/2009060308 Ubuntu/9.04
(jaunty) Firefox/3.0.11"

-- 
Bill Day
williamson.day at gmail.com
PGP Fingerprint: EE5D DE55 9EF1 E012 7417
A5F1 1D7D 0847 7785 1146