Membership 2 Registration Timing Out

When I register an account using the BuddyPress or default WP register pages, I can register with no problems. When I try to register with Membership 2, clicking the 'Complete Sign Up' button eventually takes me to a blank page. A look at the error log gives this info:
PHP Fatal error: Allowed memory size of 268435456 bytes exhausted (tried to allocate 22925 bytes)
Trying to increase the memory size did no good. This error also occurs when a member tries to select a membership option on the memberships page. It also times out.