From the error you are noting, I think I can safely assume you are using Firefox? We are currently working with Mozilla for a permanent fix after they converted their browser to 64bit only. You can use this work around in the mean time;
•In the address bar type: "about:config"
•A message will pop up for dangers of the these options agree to them.
•Search for "xpinstall.signatures.required". It should have a value of True.
•Right click on "xpinstall.signatures.required"
•"Toggle" the value will change to false.
Please let us know if you continue to see the issue or are seeing this within another browser.
Sling Media Technical Support