First, the following link will allow you to understand what the W213 error means.
Regarding the Slingbox issue, if it shows a solid network light it means that the Slingbox is a "healthy" unit and the issue is not Slingbox-related.
The most important detail is that the Slingbox is not being detected on the local network. This means that the security software might be blocking the connection between the Slingbox and the home network. We recommend you to check this link for further details.
As a final recommendation, we encourage you to use a different computer in order to set up your Slingbox for Internet Viewing (at the Slingbox location).
Make sure to follow these recommendations and let us know how it works for you.