There is a cable between the interior door handle and the door lock. However, I don't think it can be replaced independently of the door lock mechanism. I say this because I recently replaced one of these door lock mechansims due to a problem with the central locking system on my '98 V70, and the cable came as part of the door lock, and didn't look like it could be separated from it. I might be wrong - presumably the dealer knows better than me, right?

I'd recommend that you open up the door to see if you can see what the problem is before buying any parts. Like Klaus said, it's quite possibly just a linkage rod popped out of place. It's certainly more likely than the cable breaking. If you do have to buy any parts, also get a handful of those little plastic fasteners used to hold the interior door panel in place - they tend to break fairly easily when pulling the panel off.