Welcome to the forums Stiffo
When you start a thread that gives away information about the story or quests, please can you put (SPOILERS) in the title to avoid accidently revealing to a member something that another member doesn't want to know yet. This is explained in the sticky at the top of the forum entitled
"Please Read Before Posting: On Spoilers/Reporting- it only takes a minute". I'll change the title for you this time but repeated failure to do this may/can result in temporary suspension of your posting privaleges. I'll also change the title so it reflects the problem you have as you are more likely to get a response. Thank you.
As for your problem:
Once Samuel tells you to go find Dev/Null you should just be able to go to his appartment and talk to him. Is your game patched?
Edit: I've noticed you have tried to change the title

Only moderators can edit the actual title of the thread once it has been posted but thank you for attempting to change it.