yes you can burn compilations of both, just add all the clips in ConvertXToDVD and it will convert them all plus create a nice DVD menu in order to select which one to play.
Just plain text or some HTML, you can send me a zip with the images and the text at contact@dvd-guides.com and I will add it to the Linux section (giving full credit of course).
Thats really weird, and it doesn't leave any clue about what goes wrong. Try some similar program like Handbrake and if it works email ump and he may be able to help.
ump's email is working now so you should send all requests to the official Fairuse address (the one you paid to) as I cannot provide anyone with a download link anymore.
You could also use Handbrake but it won't add the subs in the mkv file, instead it will "burn" them on the video permanently. You could fix that by ripping subs manually with SubRip (guide for that coming really soon) and then create the mkv file.