exportfs: /anyfolder does not support NFS export

I am trying to export anything .... no results....

This post is like desperate action... I am not newbie with linux, not newbie with nfs (I have been using NFS for years)
But with this case I feel stupid ...no idea what could be wrong...

Details of my configuration in last posts in thread:
http://forum.doozan.com/read.php?2,12096,15422#msg-15422
...and many many before...

basicaly:
- ARMel arch (hardware :Zyxel NSA 325 V2, rootfilesystem on pendrive (/dev/sdb1 - /boot part with ext2, /dev/sdb2 - rootfilesystem), u-boot bootloader in NAND
- two hdd with mdadm and lvm ... but this is not this case
- marvel chipset
- kernel 3.13.1-kirkwood-tld-2 kernel.


PROBLEM:
any entry in /etc/exports file caused message "folder does not support NFS export" ...

no matter if debian wheezy, squeeze, testing, if folder is on ext2,ex3,lvm, if nfs3 or nfs4, directly from pendrive, anywhere...

I give up, I spend many hours on that without any result ...