Vienna Ensemble Pro
Take a look at Vienna Ensemble Pro (VEP, VEPro). There is a Master/Slave feature that let you process VST instruments (and ordinary VST effects) on other computers (and you can mix Macs and PCs).
The master sends MIDI commands to the slave, and the slave returns the result samples. All through a plain cabled ethernet connection.
I was able to identify the plugin by opening the CPR file in a text editor, looking for the track name and investigating the detailed info adjacent to it. I found something called "OriginalPluginName" and there i found the name of the missing plugin.
To me it sounds like an up/down arpeggiated saw synth.
It does sound pretty much digital and I'm sure you can achieve a similar sound in most commercially available software or hardware based synths
There is also a lot of reverb on the sound effects in background that sound pad-ish