Since we're talking about COM computer ports, I'd say you should look into your computer's operating system. The JV's OS is bound to be a great deal more robust than anything coming from Microsoft, so check system and multimedia settings first. The reset for the JV-1010 is well-described in it's documentation, which is on the Roland website.

Until my latest interface solution, I was simply using an adapter cable through my sound card's game port, and never had a problem with communication. Of course, I wasn't terribly interested in anything the JV-1010 wanted to say to me!