I'm afraid a hard reset may be the only way to fix this. The most likely possibility is that one of your Clie's system files was transferred to the E2 along with your data - this can cause all sorts of weird crashes and errors including the problem you're describing with sync, and there's generally no way to remove the offending file aside from a hard reset.
I don't believe the E2 has a built-in backup function, so if you wanted to back up your data you'd need to install some sort of backup program (like
BackupBuddyVFS). But if you can't sync then the only way to install that is to copy it directly to your memory card, for which you'll need a memory card reader - if you can get access to one of those, put the backup program in the \Palm\Launcher directory of the memory card and it should show up in your Palm's application launcher.
Most of your data should be backed up in your Palm Desktop backup folder (c:\program files\palm\(your username)\Backup), so before you hard reset your Palm, go to that folder and rename it to "Old Backup". Then, after you reset, you can go into that folder and restore any needed data files. (but don't reinstall everything from there or you'll end up with the same problem you have now) Your calendar/contacts/memos/todo entries should all be backed up automatically by Palm Desktop, and will be restored automatically the first time you sync after the reset.