Supported browsers for Client Integration Plugin 5.5.0?

I've downloaded and installed VMware-ClientIntegrationPlugin-5.5.0 for my Windows 7 Professional but I still get the error message

The Client Integration Plug-In must be installed to enable OVF functionality.  Click the link below to download the installer.

whether I'm using

Chrome Version 39.0.2171.95 m

Firefox 33.0.3 (even after I answered all the security questions to allow the plugins!)

IE 11.0.9600.17420

I'm running vSphere Web Client Version 5.5.0 Build 2026576 and upgrading is not an option.

I just need to deploy one OVF to one hypervisor , I don't need any other advanced functionality.

What browser versions are known to be compatible?