Midi Drum Track Not Reaching Output Bus

I am not really a MIDI person… Another of my legacy mixes (made in Cubase LE C.2007) includes a midi drum track that is made by the internal on-screen keyboard window method rather than via an external e-drum kit. It all used to play fine on the old software and I even have a wav/mp3 export of the completed project.
Now in Cubase Elements 7 the audio tracks for guitar, bass, vocal etc play fine but the MIDI track doesn’t. It all looks hunkus dorus on the display and I get the blue bar in the track fader going up and down indicating the channel output rising and falling as it plays.
So it’s there in the main display and the mix console but not reaching the output bus.
This is strange because I’ve not changed anything and the audio tracks play fine.
Please can anyone tell me what I’m overlooking here?
Thank you.

I’ve just been in there meddling and set up the Groove Agent ONE as a VST Instrument at the bottom then set the output of the MIDI drum to go to that. The indicator bulb was lighting up showing data in but no sound - aha - select a drumkit helped get some sound. The drum timing was way out. I discovered the drum track delay slider and set that to about 152ms. Now it all seems aligned nicely. And I can select a nice solid punk rock drumkit.

Am I barking up the right tree here or have I just devised a work around and not really addressed the problem?
Is the track delay requirement something I should expect?
Are the drumkit voices all on the same keys or is it different for different basic kits? - some kits sound weird on my project.
Are different voices affected equally by whatever time shift thing is happening. I am used to latency where there is an initial delay but this is more like an initial advance as it requires a delay of the drums to fix it. Maybe the old drum track was adjusted for latency in the old software. I dunno!

Any thoughts please.
Thank you.