Follow this guide to help you with the Hollow event for Lisbeth.

Lisbeth Hollow Event
Mysterious Ore at Bastea’s Gate Floating Ruin
Go alone to Northern walls dragon circuit and find the ore that are different from other
Go back to Aincrad and bring Lisbeth come
After that, this event is done for the first part
Investigate the rare crabs appeared in Bay Area at Graysreev
Go alone to Graysreev beach at the north area and kill the black crab
You will get key item and head back to Agil Shop to trigger an event with Lisbeth
After that party with Lisbeth and go back to Graysreev beach at the north area
Kill about 10 of the black crab and you will get another key item
Go back to Aincrad and go to Lisbeth shop
After the event you will receive Master Armor
Lisbeth Hollow Event End

Source: http://www.gamefaqs.com/boards/734608-sword-art-online-hollow-fragment/69647786 by Sunsetdeska