Starting NFS kernel daemon fail

hi, everyone, I'm trying to setup an NFS server on my PC. I recompiled the kernel, installed the nfs-utils, and also installed nfs-kernel-service. After these, I configured my /etc/exports like this: /var/owr *(rw,sync) then I chmod -R 777 /var/owr, but when I started up the nfs service: /etc/init.d/nfs-kernel-service start it showed me this: * Exporting directories for NFS kernel daemon... ...done. * Starting NFS kernel daemon ...fail! could anybody tell me what's wrong with this? thanks...