I have also tried a web install for roundcube and this is what the checker has to say:
Checking PHP version
Version: NOT OK(PHP Version 5.2.0 or greater is required 5.1.6 detected)
Checking PHP extensions
The following modules/extensions are required to run Roundcube:
JSON: NOT OK(See http://www.php.net/manual/en/book.json.php)
The next couple of extensions are optional and recommended to get the best performance:
Problem is that when I try to update I get no update in the current repositories. I remember changing reps in the ISP config installation instructions and I don't want to mess up my installation. Can you help me please?
For instance, does it make sense to dolwnlaod PHP 5.3.3 from here: http://www.php.net/downloads.php
And compile the package?