The lack of APC should not be an obstacle to installation (I've done
numerous installations without it, adding APC only later, so I speak from
direct experience). I assume you'd proceeded to the next stage (if not,
please do so). What other errors/symptoms have you encountered.
Exception is APC. We highly recommend to enable PHP APC caching system so
that your site will perform much better. However, this is not mandatory and
you still will be able to continue with the installation process.