Missing sample on Logic's ESX24 during 'How to make Progressive House' module

I’ve encountered a problem on Tutorial 5 of the ‘How to make progressive house’ module that I cant seem to get my head around.

I completed the module but upon return to it the next day it has said the the previously loaded sample in the ESX24 named Prog House 2 (this is the high bass sample) was not found and I’ve been unable to load it back in since - its seems to be stuck on its default setting and I cant seem to get this sample playing again.

I’ve been able to load this successfully in a another project but it soon goes missing again when I go into another project.

No doubt there’s a simple solution to this but any help would greatly received.