Hi!
Looks like the host detected the plugin as a false-positive. I have no idea why, perhaps some code parts resemble something for the heuristics filter.
Have you tried to install the plugin via the plugin manager? It’s much better than using FTP to upload, and might not give you this warning.
Otherwise I guess you will have to whitelist that file somehow. Maybe there is an option on your CPanel or equivalent hosting settings page, where you can whitelist files. Maybe you will have to contact the hosting provider to do it for you.