Copy of error message:
"A fatal and unrecoverable database error has occurred. This may be because the specified user does not have appropriate permissions to CREATE TABLES or INSERT data, etc. Further information may be given below. Please contact your hosting provider in the first instance or the support forums of phpBB for further assistance.

install_install.php [ 1181 ]

SQL : CREATE INDEX phpbb_sessions_session_forum_id ON phpbb_sessions (session_forum_id)

ORA-00972: identifier is too long"

Basically oracle cant cope with anything with a name of over 30 characters. The limit is 30 characters. Going off the message above it looks like the installation script is trying to create an index whos name is 31 characters long.

We've previously had version 3.0.0 working on oracle (although that was on version 9.0.1.x of oracle).

Its not a tablespace issue as the install has written 12.75Mb into the tablespace and theres plenty of room left in the tablespace.