Why the Boolean Modifier is disabled ??

Hi all,
I was creating a picture using two meshes and applying them a Boolean Modifier.

But Blender 2.61 refuses to run the Boolean operation … :no:

He says: “Modifier is disabled, skipping apply”.

But what is disabled?
Where can I re-enable it?

Because Blender has a way of making things difficult? :mad:

Thank you for your help. :wink:

I have the same problem.

Too little infomation.
What oerating system, what version of blender are you using (if not official release, what build)
Attach a blend file to your post that demonstrates the error message.