I have search these forums and the Roundcube forums and have not found a solution to this issue.
I installed RoundCube from the default script installer in Virtualmin for Roundcube 0.5.3, it seems to work OK except will not display HTML messages. I get a HTTP 500 error.
I have followed several suggestions including deleting the .htaccess file in the Roundcube directly and several others suggestions in the roundcube forums. But they are saying this is a “configuration” issue, which I don’t fully understand…