Hi there...what is happening is this: when your downloading your email onto your blackberry, it is not actually downloading the emails, it is downloading a copy of it, so, when you get back to your pc or laptop, you should download in outlook to actually pull them off the server.
You may want to check in outlook settings if you have checked "leave a copy of msg on server" uncheck this to help.
all the best!
Mega Star Media INC Support Team
Social Networking Web Developers
Reno * Canada * New York