Thank you for the whole of your hints.
I made another test, installing Fedora 18 64 bit on a new VM.
After installing I used uname -r to see that the OS version is not PAE
Then I entered yum install gcc and yum install kernel-headers kernel-devel
At that poiunt I started VMware Tools installation and I stop at the same point, because "The path "" is not a valid path to the 3.6.10-4.fc18.x86_64 kernel headers".
I looked around my VM but, givem my limited Linux skills, I was unable to locate them...
Where should I look for them?
Regards
marius