So, I robbed ol' Bishop's safe in the Shark Club, and got the holodisk and raider's map (and then I killed Bishop by boobytrapping the safe). But, when I go to either Lynette in VC or Roger Westin in NCR, no dialogue options about this ever come up. I've tried "using" the disk on them as well, all to no avail. Am I missing something here? I've already completed the quest to find out what was killing Westin's brahmin, and so now when I talk to him, my only dialogue option is "oops."

This quest is started by wiping out the raiders north of Broken Hills, and recovering Bishop's payments book from them. You can then take the book and the holodisk to Joanne, who will ask you to take the holodisk to Westin.