Hi,
There are a number of reasons why this can fail. What do you actually mean my "I can mount it from a windows server"? CIFS or NFS?
Read the manpage for exportfs and login to the filer. 'exportfs -c ip.addr.of.linux /vol/yourvol/yourqtree' also with the "rw" and "root" flags.
Enable the options 'nfs.mountd.trace' and watch the messages log.
Make sure the reverse DNS of the linux servers works or use IP address in the exports file (a working DNS is always a better plan).
Your life with NetApps will be infinitely easier in the long run if you use the cli instead of FilerView