Thanks for using our answers forum! I understand that you are unable to connect to your Slingbox and the network light is flashing. Have you tried resetting the Slingbox and running through Setup on Slingbox.com? You may also want to hardwire the Slingbox to your router temporarily just to complete the setup and then return it to the permanent location through the SlingLink.
Here is an article form our support site which should assist you with troubleshooting this issue:
Hope this helps!
The Sling Moderation Team