It seems that you are having some issues with your Slingbox SOLO since you cannot get the remote connection.
The fact that the SlingLinks and the Slingbox show solid lights means that the Slingbox is a "healthy" unit. I recommend you to go to www.slingbox.com and run the configuration for Internet Viewing one more time. The reported error code (0x8007274C) belongs to the SlingPlayer software version which is no longer supported.
If the issue persists after configuring the Slingbox through www.slingbox.com, I encourage you to contact your security software provider in order to know how to allow the communication to your Slingbox through the firewall.
The following links will provide you with further information:
Hope this helps!