tmhOauth has its documentation inside examples. Examples are very straightforward and beneficial to understand the code. You can find examples here:
You can get your own application's access tokens also and use your own tokens. Check this: https://dev.twitter.com/discussions/631
Regarding to your code in question, you get 400 error, it's different from 404. You made a bad request. From the headers I can see that you consumed your rate limit. You should wait until next reset time. Which is epoch 1347001832 = Fri, 07 Sep 2012 07:10:32 GMT
As a side comment, you can use Twitter API 1.1 which is presented last week. Which gives more rate limit.