Or only after you update redis-server?

When I tried to reproduce your issue, I can't.

As I posted above, when I first start the appliance I get a message like "Oops, something has gone wrong", then after adding Debian wheezy-backports repo and updating redis-server it works fine.

I am using an OpenVZ template (rather than the VM build you are using) but I doubt that is the issue (both of them are built from the same source - ISO). I have 1GB RAM allocated + 1GB swap and it fluctuates between 700MB-950MB RAM usage and has about 200MB-300MB in swap. It runs quite sluggishly but otherwise ok (it takes a few minutes to get started, both initially and after updating Redis-Server)...

I suggest that you start again from the start. Firstly I suggest that you verify the image isn't corrupt (don't just download it again - I have had occasional issue with a corrupt SourceForge mirror, just downloading it again won't confirm that the file isn't corrupt!)

Double check that you are getting the "Oops..." message in your web browser when you first launch it. Then from the commandline run these three lines:

echo -e '# Backports repository\ndeb http://ftp.debian.org/debian wheezy-backports main' >> /etc/apt/sources.list.d/wheezy-backports.list
apt-get update
apt-get install -t wheezy-backports redis-server

Let me know how that goes...