Before Ollies confrontation with the group about nominations he had apparently been called to the diary room and told by big brother he wasn't giving them the right stuff/material.
Linda quotes:
"He's done that because Big Brother called him up and had a go at him earlier.....That's why Ollie's done that, he's done that for Big Brothers Benefit"
"Big Brother had a go at him for you know, not giving them the right stuff"
I actually believe this and its really out of order if the producers are telling the housemates how to behave or letting them know they are not being entertaining enough.
Starts from 0.17 seconds in: