Missing packed-refs in both cases.
Wheat works on my local machine.
Did get it to work on ec2, after doing a git pack-refs.
heroku logs
2011-11-23T02:59:24+00:00 app[web.1]: /app/node_modules/wheat/lib/wheat.js:75
2011-11-23T02:59:24+00:00 app[web.1]: if (err) { throw err; }
2011-11-23T02:59:24+00:00 app[web.1]: ^
2011-11-23T02:59:24+00:00 app[web.1]: Error: ENOENT, No such file or directory '/app/packed-refs'