Need suggestion for a free AVI->DVD converter that can merge AVI-files

As the long topic title says, I need a free AVI->DVD software that can merge two AVI-files into one and encode them to DVD-format. It’s a plus if it can output the data as an ISO-file, but it’s not necessary.
I’m currently using Avi2Dvd, but it fails when I merge files.


EDIT: It’s working now.