exif etc not installed

I get this message when I try to install on install/index.php

xsl extension isn't installed. Warning! Dolphin can't work properly without it. 
fileinfo extension isn't installed. Warning! Dolphin can't work properly without it. 
exif extension isn't installed. Warning! Dolphin can't work properly without it.

I am trying to install in subdirectory on a VPS server. I have access to root.

These are pretty common error messages on a new server. Check your PHP.INI and Apache config files for these extensions and implement them. Sorry I can't be more specific but I'm working from an iPad.

How is this VPN configured?  Dolphin 7.2.x requires fileinfo and exif extensions and xsl.  If they have not been compiled into php, you will need to add them.  If they are there, you may just need to enable them.  If php is running as an Apache mod, you will need to restart Apache after making the changes.