I too have been having trouble getting pBuffers to work. Are pBuffers really supported?
All attribute lists I've created for which included the pair:
EGL_SURFACE_TYPE, EGL_PBUFFER_BIT
cased eglChooseConfig() to succeed, but that method returned zero configurations. (This includes the config from the sample on page 48-49 of the OpenGL ES 2.0 Programming guide.) If I set egl_surface_type to EGL_WINDOW_BIT, the config succeed, but as I rather expected, eglCreatePbufferSurface later returned EGL_NO_SURFACE.
I'm using a Radeon HD 4800 card, and the 1.4 version of emulator.