You might be having an addressing conflict with the SlingLinks. Every network device has a low level address known as a Media Access Control (MAC) address. It might be that the SlingLink is somehow conflicting with your wireless access point. Actually, I'm not sure you mentioned if you're using a seperate access point or if yours is built into your router. Actually, I don't think you were specific with which router you have in this setup.
It definately sounds like there's a conflict with the wireless access point and the SlingLinks.