Hi and help.

Last night I downloaded a film and when it finished I noticed it had a file extension of .MKV.  Ive never come across this before?  

I have downloaded AVI2DVD software and was wondering if its compatable to convert it from .MKV to DVD?

I tried last night and it kept coming up select Audio Stream?  When I went to the input screen the 3 Audio stream boxes are all blank, theres no options to choose from...?  confused...

If by chance if this conversion is at all possible, could you email me a step by step guide of how to do it?

Any help will be greatfull received.  I have downloaded a player (VLC I think) Player so can watch it on my laptop, but the pic sticks and I would really like to watch it on my TV via my DVD player..

Thnx in advance.