Yes, it's not a good idea to block with almost all of the countries selected. In regards to your boot issue, you should have previously received "pfctl" memory failure notifications??
Also, unless you have open wan ports, you should use "permit outbound" rules as pfSense is a state full firewall by design.
pfBlockerNG, is more than a country blocker, you should read the thread I linked above for other threat source lists which can help protect your network from known malicious ips.