Thanks all. But still no good. I thought maybe the installation was corrupted somehow so I completely uninstalled Eclipse, Java--all the stuff related to BB development that I had installed and then reinstalled everything from scratch.
When I try to debug the code that sahil_khanna posted, I get the error messages that I previously posted. If I do press "don't ask", it eventually just tells me that it "Some debug information is missing. Not all applications may be debuggable." Then as I was writing this, I noticed that all of the files it previously said it had trouble loading had the word "debug" in them. Then it finishes loading the simulator. But HelloWorld never shows up anywhere on the simulated BB.
So I closed the simulator and tried again--this time RUNNING it instead of DEBUGGING. But even though HelloWorld still doesn't show up on the BB, there are no error messages in Eclipse.
Handspring Visor -> Handspring Visor Deluxe -> Palm Treo 650 on VZW -> Palm Treo 700p on VZW -> Blackberry Tour 9360 on VZW