Running Oracle 8i in HPUX 11.0 environment

sqlplus gives the following error if I attempt to login as 'sys'
ORA-09925: Unable to create audit trail file
HP-UX Error: 13: Permission denied
Additional information: 9925

Enter user-name:

Now the unix userId I've logged in as is a member of the DBA group which has rw- righrs to the directory that the OS audit trail is written to and, to make matters weirder...

If I log in to sqlplus as system, then logout (Cntl-d), I can login to sqlplus as sys without error.

Recently, the application logical volumn was extended on the server, but Oracle is in a completely separate logical volumn, so this may have nothing to do with the issue.

Any thoughts on this dilemma would be appreciated, I'm really scratching my head. Thanks, Dan