[horde] Image preview doesn't work in HTML Composition.

[김 덕곤]

I have two horde installations.

One is working correctly.
The other one is not working.

Here is scenario.
new html message with checked 'HTML Composition' .
drag and drop .jpg file into html composition area.
Instead of image I dropped, 'IMG Icon' appears.

Double click on image to check URL.
/horde/imp/view.php?actionID=compose_attach_preview&composeCache=toi3KeZlo73F1tpYZQ78yA9&id=1

Open in a new window.

'''
A fatal error has occurred
Could not display attachment data.
'''

I use syslog as logging system.

I checked syslog and apache error_log, there was no error.

Where do I need to check? What I am missing.