Tiberius et al,
Each saved game only seems to include those xx files that have changed, so if you are in Verdistis only (x1), the x0 and x2 files are not saved, and whenever those files are needed again (because you traveled somewhere else) they are loaded from the dynamic folder. Presumably, this was to limit file size of saved games.
I figured this out because I had a crash during one of the little ad movies while starting the game (the one with the tomb...only time this has happened to me). When I restarted, the game asked if I wanted to clear the dynamic files, which I did, not realizing what would happen. I was in the dark forest, and all appeared to be fine...that is, until I teleported to my other pyramid in Aleroth and found the room reset to it's state at the start of the game (including no pyramid), because the dynamic folder had no x0 files.
After looking over the threads here, I copied the x0 files from one saved game and the x1 files from another, fortunately losing very little in the process.
Now I'm wondering if I should upgrade from 1.33a or just keep playing.
Anyway, I hope this might help someone else who unwittingly deletes the dynamic files.