I don't know what exactly caused it but I cannot get Arcade Gannon to follow me anywhere anymore. It's not that he doesn't like my karma or actions (I'm very good) so I'm not sure what the cause or solution is. He is in the Lucky 38 and the dialogue option pops up for him to follow me but he keeps claiming that I have too many followers even though I have none. I have tried and tried again to figure out a solution but it has gotten so annoying that I quit playing for awhile. any help would be appreciated.

Maybe you told your old followers to wait somewhere and didn't actually get rid of them

I had the same thing happen to me dude. After you play a while and read this forum, you realize if it happened to you it also happened to someone else. As far as Arcade messing up, I even went back quite a few saves to see where it happened but it must have happened quite early on. For me, I had been hanging out with Arcade for quite a while to get his quest to go. I decided to finish up Boone's quest but when I went to get Arcade back there was no option for him to join up anymore. So I just kept Arcade around until his quest triggered and then dismissed him after I completed it. It's annoying but as far as I know I don't think it can be fixed. I wonder if instead of telling him to go to Lucky 38 if went to the Mormon Fort if it would work. Sorry I couldn't offer a better solution for ya.