HELP... site problems after trying 3.5.3!!!

Sequence of events
- I created a 'sliding door option for an Atahuapha site at
http://www.whiteravencenter.org/
almost a year ago, posted it here, and installed it on on other sites as well, like
http://www.raceskitrader.com/
- updated Wordpress to 3.0 for both sites- everything worked, including the sliding door menu, but
encountered problems on the White Raven site like others were having using Atahualpa with the
new 'draft post' features, came to this forum where it was suggested that AT 3.5.3 had solved
some things. (Running AT 3.4.9 at the time)
- installed AT 3.5.3 and immediately the sliding door menu disappeared.
- not acceptable, so rolled back to AT 3.4.9, sliding door menu still disappeared.
- rolled back to AT 3.4.1, still broken - sliding door menu still disappeared.

Not a WP 3.0 problem, since the code still works fine running 3.0 and AT 3.4.4 on the second site.
I've tried to compare the working site with the broken one, the code I added (entirely in AT supplied windows, core files never touched). looks identical.

I did do a backup, but my host doesn't provide phpMyAdmin installed, and I haven' had to install or use it in several years - not sure I remember how to do it and meanwhile the site is seriously crippled...

Please help! -- Jack