Problem with the F2L (Fridrich)

[Cubeginner]

I just began learning the Fridrich method 2 days ago and I'm sort of getting the hang of F2L, except I have one problem. Whenever I need to make the 4th 2x1 block it seperates a solved one. What am I doing wrong? I learned this off a youtube video I found but it's possibly not the best, so if you could explain the solution to this problem to me or redirect me to a better tutorial I'll be grateful.
Thanks

 

[JasonK]

Rotate the top layer so that when you do the move to "hide" the corner, it's bringing an unsolved slot to the top layer.

Also, here's a good tutorial.

 

[cubelover111]

Watch these vids
part 1: http://www.youtube.com/watch?v=k-xbcAMfWwM
part 2: http://www.youtube.com/watch?gl=CA&hl=en&v=4GxLM_dZqg4

 

[Cubeginner]

Thanks alot! It helped my problem
Gonna practice now

 

[jla]

Seems like you've already got help but scince it's your first post, Welcome to speedsolving