Recovering ORACLE db after system crash

We are currently running ORACLE Version 6.0.31.0.1 on an RS/6000, running AIX Version 3.2. A power failure took out the machine the other day while ORACLE was being used. When the machine was brought up again, we had trouble starting ORACLE. The error message we got was ORA-1545 (see below). So to get ORACLE started I commented out the rollback_segments statement in the init.ora file and started ORACLE.
Using SQLDBA to look at the rollback segments table indicated that one of the rollback segments had a status of "NEEDS RECOVERY". I couldn't drop the table because ORACLE told me to put it offline, I couldn't alter it offline either, neither could I recover tablespace "rollback_segment".

In the end we were desperate so we restored from tape.

What should I have done?

Oerr: Version 6.0.31.0.1 - Production on Wed Oct 07 08:47:21 1992

Copyright (c) Oracle Corporation 1989. All rights reserved.

01545, 00000, "rollback segment '%s' specified not available"

// *Cause: 1) Try to acquire offline rollback segment during startup.


//	   2) Try to drop a rollback segment that contains active transactions.


// *Action: 1) Bring the tablespace containing the rollback segment online or


//	       do not specify the rollback segment in init.ora.

//	    2) If the rollback segment is in use, shutdown the instance using

//	       rollback segment, else if the rollback segment needs recovery,

//	       find out the errors that are holding back the rolling back


//	       of the transactions and take appropriate actions.



-- 
Brad Keifer, BHP Information Technology, Newcastle Region, Australia
PO Box 216.  Hamilton.  NSW.  2303
internet: brad_at_cerberus.bhpese.oz.au            Phone: +61 49 402126
                                                Fax:   +61 49 402165