Eu tenho o mesmo problema e encontrei uma postagem aqui dizendo:
NFS server has an option of working in insecure mode (Allowing higher incoming port numbers). Windows NFS client often uses higher port numbers. You can enable this option by adding an option to the share Example: /share *(insecure,rw)
You can also try installing Windows services for UNIX package which contains a nfs client. You can try to connect the nfs server using this utility and cross check again. You can download the package from the following link http://www.microsoft.com/downloads/e...displayLang=en
Eu mudei o / etc / exports de acordo com ele (adicionando a opção insegura) e ele funciona. Espero que isso ajude.