Thanks for the code and help.
I debugged a little and it stops at
if ((status = clGetPlatformIDs(numPlatforms, platformList, NULL)) != CL_SUCCESS) {
in main.
No idea why.
Also just heard that the current fedora 17 kernel has a problem with NFS and automount.
Will try now to get and an older kernel.
Currently I am running 3.6.1-1.fc17.x86_64.