I have 2 large avi files to which I have added chapter markers. Do I have to render these to eithe one large AVI or a MPEG2 files before importing into DVDA? In other words can DVDA treat the 2 files as one & retain the markers or would I have to redo them again.
No, DVDA can't treat them as "one" because that would be a blend of two files in DVD A, and DVD A can't blend/mix files. DVDA CAN have an end action that says "when the first file is done, immediately start the second file" so the viewer will see the two files as one, but they are still separate files. There might be the slightest gap as DVD A goes from one file to the next.
DVD A will read the markers in both files, and both files can be used to create chapter points.