IMAP connection error

[dolkfm]

Hello,
I have a problem with upgrading roundcube on my synology diskstation.
old version : 0.4.2
new version: 0.6

I tried both, uprgrading the old install and install the new version on a different location with anorher database.

This is the entry in my error log:
[22-Oct-2011 11:20:05 +0200]: IMAP Error: Login failed for test from 192.168.0.66. Empty host in /volume1/web/mail/program/include/rcube_imap.php on line 199 (POST /mail/?_task=login&_action=login)

I tried different settings for $rcmail_config['default_host'] = 'localhost'; (172.0.0.1, my server name, my server ip)

IMAP server is running, becouse i can login with outlook and the original roundcube 0.4.2 is working now also (even with the already adapted database from version 0.6)

anyone??

[dolkfm]

Now i have tried some several other things:

First i tried a fresh install of version 0.5.4. This ended in the same result with the same error code.

After that i tried a fresh install of version 0.4.2 on a different location (so now i have 2x the same version with each it's own database) and this is all working.

What has been changed between these versions why it does not work anymore with the latest versions??
(When installing/setting up all check's seem ok)

Hope this gives more usefull information

[dolkfm]

Now, i've tried to install version 0.5 This is also returning the same error code.(Emty host in program/include/rcube_imap.php )
What has been changed between version 0.4.2 and version 0.5???

Isn't there anyone??
?