I understand that you are having an issue with streaming your Slingbox to your iPhone 4. It sounds to me like you may be having an issue with port forwarding settings on your router at home. Here are some helpful links to assist you in troubleshooting:
If you still have any issues or questions about the port forwarding settings on your router, you should be able to get more information from your router manufacturer.
Hope this helps!
Sling Media Forum Moderation Team