Luminance texture not working

I have been working on an OpenGL project using GLUT through XCode 3.0, however I have been using GL_RGB32F_ARB in the glTexImage2D call for internal data. However, I would like to use GL_Luminance32F_ARB. And when I create a new texture, it works well. However, when I make a texture from the FBO, then it brings up random values.
I am really stuck. And it is driving me crazy. It doesn’t seem like there should be any reason why it shouldn’t work.

I’m running OS X 10.5.6
on a MacBook Pro, with the ATI X1600 mobility graphics card.

I thought it was a driver issue, but seeing as the texture i create works with GL_LUMINANCE32F_ARB, the texture created from the FBO should also work

What makes you think the hardware can render to luminance?

This case is specifically not allowed, per the definition of “color-renderable” in the FBO spec. The driver is reporting FRAMEBUFFER_UNSUPPORTED in this case, and you should be checking for it.

Thank you for the reply.
is this a problem with both ATI and nVidia cards, or just ATI?

The spec forbids it, so it applies to all video cards.