Just answered my own question. I burned the disk- successfuly- so long as it's played back on the computer! However, when slotted into my domestic (Sony) DVD player, hooked to the TV, it reads "Disk Error".
I suspect that its the .avi format- anyone out there able to help? If the problem lies with the file type, what should I do/ have done to get it into a playable format for playing on the domestic DVD player??