When i First got my blackberry and setup my email account's, everytime i sent an email i got that same email back. many of my friends have had this same problem and its very annoying.
there is a very simple solution.
1.Got to
www.att.blackberry.com (this is for people with att, im sure there are similar sites for other providers)
2. Once logged in you will see all your email accounts.
3.You will see a column on the righthand side "filter" hit that
4.Hit "add new filter"
5. name your filter anything you want
6. Apply filter to "from field"
7. Where it says "contains" type in your full email address
8. Save