CONFIGURATION ERROR defaults.inc.php was not found.

[Abraham777]

How can re-installing roundcube on Centos?

[miami]

I had the same problem but got away with chmod'ing
/etc/roundcubemail/defaults.inc.php
to just 644, which avoids enabling execute flags.

Yep, this true.
644 more secure.

I haved some problem - this is TRUE!!!
thanks

[bob_2222]

У меня выдавал ошибку

CONFIGURATION ERROR
config.inc.php was not found.
Please read the INSTALL instructions!

Решение
chmod file
/etc/roundcubemail/config.inc.php
изменил права доступа к файлу с 640 на 644
И всё заработало.