I think one of the greatest problems arise when people lack the skills to manipulate technology. Some problems which may arise is that those applying for some jobs may not understand the application process, given the move away from paper applications. I would imagine that HR people have more issues with people applying and not understanding the process than fighting the technology itself.
One challenge is the challenge of privacy. HR managers have all of this information about all the employees in their firm at the tips of their fingers. They and those who work in HR under them have to be very ethical because it is much easier than it once was to snoop into people's lives. They also have to have really good security so as to prevent their databases from being hacked into by people trying to steal information.