session_start(): Failed to initialize storage module

[Linda Lee]

I am studying samples of a book to save session handler to a table in
Oracle. But I got error after setting "session.save_handler=user":

Fatal error: session_start(): Failed to initialize storage module. in
c:\phpcode\wrox\code_downloads\ch08\handler.php on line 9

What could cause the problem? Is there a good sample in saving session
handler into Oracle (not MySQL)?

I use PHP 4.3.3 with Apache.

Thanks a lot.