Hi Stephen,
I am assuming you are using IE-10 browser ,if that is the case please make sure you are using IE-10 with compatibility mode , once you change it to compatibility mode it should start working
Discovery will not work with 8.2 the reason being SNMPV3 which SM 2.2 will not support , once you check with IE-10 compatibility mode Add should work and you should be able to add the filer to System Manager , if browser you are using is not IE-10 then please try with some other browser and let us know if it still doesn't work.
Regards,
Vinay