Offhand, I would say that it can't find your config file. I would recommend using a full path, ie, change
Log::Log4perl->init("log.conf"); to
Log::Log4perl->init("C:/Perl/site/lib/Log/Log4perl/log.conf");

Remember, if you don't give a full path, the path is interpreted relative to the currrent working directory of the running script - not the location of the perl modules you use.