Actually, I believe I may have found the problem. It appears to have something to do with using Sybase Central's unload feature. I'm using Sybase Central's menus to run Tools, SQL Anywhere 11, Unload Database... When I got to the screen that says "Select the Server or Local Computer", I would select "Save the data files on the local computer using OUTPUT statements", and also selected "Use INPUT statements to reload the data from the local computer". One or both of the selections appears to have caused the problem. When I instead selected "Save the data files on the server computer using UNLOAD statements", and also selected "Use LOAD statements to reload the data from the server computer", and then used Interactive SQL to run the reload script that was generated, this appears to fix the problem.
I think the first set of selections I used should have worked, but didn't. I guess it has something to do with my database having UUIDs. The errors I received related with running Interactive SQL on the reload script, and said that it couldn't reload UUID fields.