It seems that you are having some issues with your Slingbox Classic since it does not keep a steady network light.
Even though you have already applied some of the most common troubleshooting steps, I recommend you to check this link and follow the included recommendations:
The Network light on your Slingbox blinks or turns off
If you follow the instructions and the issue persists, I recommend you to give us a call as soon as possible since this issue might be related to a faulty power adapter. The following link will provide you with the contact information, just make sure to use the information located on the right hand side of the screen to select the options for your country:
Hope this helps!