Comment 16 for bug 833300

I reproduced this problem per your setup on Ubuntu 10.04 LTS server and client. There nfs4 would not work (e.g. permission denied), but nfs3 works. However, on Oneiric as server neither nor works:

spindler@spitfire:~$ sudo mount -t nfs -o vers=3 meteor:/home/spindler/export /mnt-meteor
spindler@spitfire:~$ /mnt-meteor/hello
bash: /mnt-meteor/hello: Permission denied
spindler@spitfire:~$ mount -v | grep mnt-meteor
meteor:/home/spindler/export on /mnt-meteor type nfs (rw,vers=3,addr=192.168.1.122)