[imp] imp update to version 5.0.15

[Daniel]

Hi,

today I have updated to version 5.0.15 of the imp. The update was performed
from the version 5.0.11. Since the update I get the following error in the
horde log:

2011-11-30T07:33:13+01:00 WARN: HORDE [imp] PHP ERROR: asort() expects
parameter 1 to be array, null given [pid 15998 on line 38 of
"/var/www/path/to/webmail/imp/lib/Menu/Dimp.php"]
2011-11-30T07:33:13+01:00 WARN: HORDE [imp] PHP ERROR: array_keys() expects
parameter 1 to be array, null given [pid 15998 on line 41 of
"/var/www/path/to /webmail/imp/lib/Menu/Dimp.php"]
2011-11-30T07:33:13+01:00 WARN: HORDE [imp] PHP ERROR: Invalid argument
supplied for foreach() [pid 15998 on line 41 of
"/var/www/path/to/webmail/imp/lib/Menu/Dimp.php"]

I can not really find the error. Can someone help me?
Thx Daniel