Failed to install MinimServer - Java not configured properly DS213

[Barbie-qu]

Hi,
I have a Synology DS213 running DSM 5.1-5021, and I have Java SE v1.8.0_6-0029 installed.

When I try to install MinimServer it fails after the 'Accept licence' page and I get the error messge:
Failed to install "MinimServer". Java is not installed or not properly configured. Download and install the Java Synology package.



I thought this might be a similar problem to the one described in the first half of this thread: problem installing minim server on Synology NAS DS212J

So, I have tried these things:
Downloading and installing using different browsers (Chrome 39 and IE 11). Install still failed, same error message.
Installing latest version of Java SE 8 (I was previously running an earlier version of Java SE 8). Install still failed, same error message.
Manually installing DVBLink Server to check whether this is a MinimServer specific issue. DVBLink Server installed without problem.
Tried installing BubbleUPnP Server v0.9 Install failed, same error message.

One more thing, I am trying to do this remotely from the server. I cannot get on the same network as the NAS at the moment. Could this make it more likely that the Java package has somehow been corrupted?

Any ideas welcomed.
Tom