(IOS) OpenGL ES 2.0 won't run on my ipod touch 4th gen, but 1.0 will.

I have Unity 3D 4.1.2 Pro Trial version. I have applied depth of field onto my camera, which might be the problem. I really want to keep it since it adds a nice affect. I selected OpenGL ES 2.0 in the player settings and ran the game on my iPod Touch 4th generation 16GB. It started to play the music, then crashed on "Hidden/Dof/Bokeh34". Then I ran it on OpenGL ES 1.0, and it worked perfectly. I saw http://forum.unity3d.com/threads/138676-Remove-a-shader-to-avoid-crash-on-some-ICS-devices, and I deleted the script. It came up with about 8 errors, so I put it back. It crashes all the time! Help is really appreciated.