ARGH! Everything installed, now time to run that pretty config tool and.... Requires php v5.2.0. CentOS includes v5.1.6 I guess my options are to install an older version of roundcube, d/l the source and recompile, or search for a backport of php 5.2.0 to CentOS... DOH! DOH! DOH! DOH!
Please be aware that some older roundcube versions had a bug that allowed hackers to upload files to your server. I know several systems which had been hacked trough this vulnerability in roundcube.