Oddly enough, I went to the Moodle install this morning and, viola, everything worked (except that I had to manually install the template from the admin pages). I'm guessing that this has something to do with my server host's cache (and perhaps the suphp issue that you mention, Helen). I've saved this message in case I run into any other issues down the line.
Many thanks to everyone who helped me troubleshoot this problem! Moodle and its community do indeed "rock," as the kids say.
Installing and upgrading help
Fantastico Install Leads to 500 Internal Error Message
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