[Q] Can't enter recovery mode topic

excuse me sir, i'm new here. I got a new core here and i interested in moster ROM in this thread ( http://forum.xda-developers.com/show....php?t=2520999 ) so i started to instal CWM recovery. i've followed this step ( http://forum.xda-developers.com/show....php?t=2517850 ) because in 1st it didn't work i try the second one.

it worked i can enter recovery mode now, but because my fail, i'm not instal the custom rom but just flash it all. it's ok missed my data, but it booted normally like first buy (it said need soft update, etc., and i want to try back again to instal the monster rom again, and i try to enter recovery mode again. but why after i press vol+ > home > power after samsung logo it just went black? after holding it about 30s it still blank and if i released the button it booted back to normal. what's the problem bro pls help. i'm just new in this modding world :fingers-crossed:

*note : i mean what is that problem means? am i need to reflash it through odin like this ( http://forum.xda-developers.com/show....php?t=2520772 ) said, and start instal cwm all over again or there's is another problem here? a help will be very appreciated here :)