From the state you indicated, you can squeeze more information from Clue # 7
# 7: "Among the person who started the lolcat craze and the Flash programmer, one is Marley and the other arrived on Monday."
Marley is already associated with Tuesday. So lolcat and Flash have to be either Monday or Tuesday.
From clue # 10, lolcat can never be PHP (all five individuals are different people). So after using this fact in the left side of # 7, Marley and Monday have to be associated with either Flash or something other than PHP. I.e. Marley and Monday cannot be PHP.
If I got this right, then placing all these additional constraints will lead to the solution.