I need to solve a transparency problem.
To do that, I want to use glSampleCoverage
but it makes my program crashing.
I use Ati lib.

Does anyone meet this problem ??

from the GL spec :
…Applications must obtain a multisample-capable context using the
new interfaces provided by GLX 1.4 or by the WGL ARB multisample extension.
Multisampling was promoted from the GL ARB multisample extension…

Are you under Windows ? So you need to get the entry point at runtime with wglGetProcAddress (or use an extension loader library, like glew).