What are you trying to accomplish?
It is my understanding that since_id refers to the TWEET ID to start returning from.
max_id refers to the maximum tweet_id to return (they are assigned sequentially as a really big integer).
Since your since_id and max_id are the same, you are effectively asking for tweets whose integer id is over 10 but less than 10. In other words, nothing at all.
If you want the last 5 tweets on a timeline, using either the screen name or user id with count=5 should do the trick