Export failed only on vol01

Hi all,
I was trying to export tables on Sun Solaris Box. First I logged in as Oracle user and I was in /home/oracle. export command started exporting but failed because of space issue.

I have about 159 gig of space on vol01/ where I am trying to export byt it was failing with
exp- 00028 failed to open mytable.log
I also tried logged in as root to do the export but I have the same error. Could any one make a suggestion?
When I do exp help=y on the vol01 dictory it say "exp command not found.
Any suggestion will be appriciated
Thanks

Ok, the obvious questions first.

Are you sure the mount point exists for blah_blah.log?

DO you have write rights on that mount point when logged in with your current ID?

have you laid down a filesystem on vol1?

Thanks for all the replies. I fixed the problem. I created a file on the vol01 and changed the ownership and gave 777 on the file and tadah it worked.
Again thank you

Gotta ask the obvious questions first.