You coud not add them since you searched for Crono and Rhas, but they use DIFFERENT steam names, being; Rhax one is Dynpuoxz (enter that at add friend) and cronos is Crono908.
No I'm not that thick =)
I copies the name Crono908 and Dynpuoxz and pasted it into the the player and groups search in steam community and it didn't work. Although I AM thick enough to have not seen the "add a friend" button on the friends window
Anyways, got them added.