During the install on a VPS I get the error "Can't find filesystem to check or filesystem not mounted with quota option." What's wrong?

This error means your VPS provider does not have Second Level Quotas enabled in Virtuozzo/OpenVZ. It is safe to complete the install, but InterWorx will not work properly (specifically you won't be able to create SiteWorx accounts) until this is fixed. You will need to contact your VPS provider's support department to get this turned on.