For some reason double-clicking on Spark doesn't initiate dialogue. He moves around the town (I've encountered him at home, at the inn, and at his father's shop), but I can't seem to talk to him. I have tried restarting the game, but it didn't resolve the problem.

Any help would be appreciated.

Are you using Exult? Or DosBox? Seems like a bug of some kind.

I'm using DOSBox at the moment.

I have just installed the last version from GOG, using DosBox on a Windows 7 32-bit and I am able to speak to Spark as normally. I seem unable to reproduce this strange behaviour.

Which operating system are you using? Did you modify the DosBox config file?

I'm using Windows 7. I didn't modify anything, but I did notice that I have to run Ultima VII as an admin, otherwise it doesn't start.

I'll try starting over from scratch (as opposed to quitting out and reloading my saved game) and see if anything is different, as soon as I get a chance.

Thanks for your prompt replies by the way.

Try installing everything outside of Program Files.