If this happens to be a Debian-based system, you could install the module via sudo apt-get install libdigest-md5-file-perl. Using local::lib, as you appear to have done, might be possible too, as long as you install the modules in a location that the webserver can access, i.e. not /root. We'd need to know more about your server set-up to give you better advice though.

If all this gets too complicated, then note that Digest::MD5::File appears to be a convenience wrapper around the core module Digest::MD5, which you could use instead.