I understand that you are having some issues with your Slingbox Classic which has stopped working after the last update.
The main issue is that the web-based SlingPlayer version does not support the Slingbox Classic. That's why you might be having this specific issue. The following link will allow you to get the information about the compatibility list:
Which SlingPlayer software works with my Slingbox?
In this case, your only option is to download and install the SlingPlayer software on your computer. The following links will allow you to get the SlingPlayer software for Windows or Mac computers:
If the issue persists, I recommend you to check the following link. It will allow you to know if you need to update your Operating System or the web browser version in use: