Hmm, it sounds like there must be some conflict between how you edited functions.php (or the membership plugin you are using?) and the WPJM Resume Manager add-on, which is preventing you from selecting the private pages you created as the Submit Resume Page, Candidate Dashboard Page, Resume Listings Page in its settings. Since the Resume Manager add-on is a premium add-on, the WPJM staff will only be able to help you via logging-in to your account and submitting a ticket, here.
In case it is helpful to mention, I use Ultimate Member to make pages (or even just parts of pages, using shortcodes) private by user role in tandem with the WPJM plugins, which has worked really well.