Since others on here can't test your security cameras did you contact Amcrest about their software and it's compatibly with FF? Not all browser work the same way.

Please read my question - it's not the cameras. Fire fox will not allow "webplugin.exe Setup" to download. "webplugin.exe Setup" works fine with 7 other browsers. It worked with older issues of Firefox. This is no big deal, I'll remove Firefox & just use another browser. Thanks anyway.