I am having a similar problem. My Solo has been working perrfectly for two-three works. In the past few days I have been getting "Unable to find a Slingbox with given Slinbox ID (Code W123). Then it asked if it wanted to continue; I hit the Yes key and everything worked okay. But not today ... it keeps coming up with the same "unable to find ... " message. Am out of the country and therefore unable to reset Slingbox at home
Since your Slingbox is not detected on a remote location, it's important to mention that some Internet security and personal firewall software may interfere with your Slingbox, as well if the Slingbox it is not saved on your Sling Account it won't appear on the SlingPlayer either. Make sure that your Slingbox is listed on My Sling Account page and also try to log out and log back in from Watch on Slingbox.com.
If the issue persists, this might be a problem with the Internet Viewing settings. Feel free to visit this link in order to retrieve the instructions for this configuration,