I have finally gotten MythArchive to work!
However, my recorded programs as well as all the images in the DVD menus are distorted into letterbox format rather than the recorded 4:3 aspect ratio. Is there someway of forcing 4:3 and removing the 16:9 anamorphic setting? I tried adding "-v noletterbox" as a command line switch in the mytharchive settings for dvdauthor, but mytharchive crashed when it got to that point in the script. I should mention that I'm using SVN revision 10493.
For those of you who are interested: I started with a fresh install of R5C7 and followed the instructions at KnoppMythWiki.org for CompileMythTVFromSVN. For Mytharchive, I followed ONLY the last part of the MythArchiveHowTo at KnoppMythWiki.org from the point where it states "Now for the MythArchive specific stuff:" The rest of MythArchiveHowTo should be ignored as it messes everything up if you use revision 10493 or higher.
After rebooting, I cleaned up the MySQL tables because the database schema changed somewhere between R5C7 and 10493 (according to a post I read somewhere). I followed the instructions given by cesman in http://mysettopbox.tv/phpBB2/viewtopic.php?t=1043 I think my messed up MySQL tables was the primary reason why I had never had any previous success with SVN and MythArchive. Cleaning up the MySQL tables also fixed various other playback anomalies I had been experiencing in MythTV.
I also had to change the temp directory location for mytharchive. The default is /tmp, which is on my smallest partition. I changed it to /myth/tmp instead. The settings for mytharchive are located under Utilities / Setup, Setup, Media Settings in myth's frontend.
(For the record, I discovered something hadn't gone right during the installation of the new rev. 10493 mythplugins because MythTV complained when I tried to set up any of the items in "Media Settings" from the frontend. It told me I had to do a "make distclean," which I did in the /svn/mythplugins directory. I then recompiled mythplugins and reinstalled.)