Try plugging in a thumb-drive. I don't have the exact specs for the BD-P1590, but I believe it is similar to the BD-P1600, which doesn't have onboard memory. The streaming content needs a place to buffer, and a thumb-drive should provide that space.
We just hooked our Samsung BD-P1590 to our 2wire DSL modem via ethernet cable. After plugging in the machine and turning it on, it updated the firmware. I followed the network setup instructions and a connection test says our network is working properly. None of the applications will connect and they all say I am not connected to the internet. My dsl is working fine on our computers (wirelessly via apple airport), I disconnected and reconnected everything and that didn't help. I also made sure the time was set correctly because that was mentioned a lot on the forums. Anything else I can do?