Thanks for the suggestions. I did some more investigating, and here's what I found out:
1. If I go to a Linux box and log into DreamHost from there, the problem goes away. So that means there's definitely something about my Mac OS X workstation that's causing this problem.
2. I'm running bash, but there are no bash settings in my user account causing this problem. I've confirmed this by logging into a newly-created user account on my Mac OS X box and then logging in to my DreamHost account, which still gives me the same problem. I also deleted my .bashrc and .bash_profile, created a new terminal window, logged on to DreamHost, and still had the same problem.
3. I tried doing the "bindkey -v" command, but it appears that this is not recognized in bash. From my bash shell, I ran tcsh, which got me a tcsh shell, and that recognizes bindkey, but it gives no output. I tried logging on to DreamHost then, and that still gives me the same problem. I think that rules out bash as the source of the problem, but I'm not entirely sure.
Any other suggestions are welcome. Thanks!