Postgres will not start due to corrupt index

We are running Postgres 9.1.3, and after stopping it by physically shutting off the machine, we rebooted and now get this error whenever we try to start it.

2012-10-02 13:54:30 PDT LOG: database system was interrupted; last known up at 2012-10-02 13:46:20 PDT
2012-10-02 13:54:30 PDT LOG: database system was not properly shut down; automatic recovery in progress
2012-10-02 13:54:30 PDT LOG: redo starts at A/764C4C0
2012-10-02 13:54:30 PDT PANIC: GIN metapage disappeared
2012-10-02 13:54:30 PDT CONTEXT: xlog redo Update metapage, node: 1663/899422/21182896 blkno: 2
2012-10-02 13:54:30 PDT LOG: startup process (PID 940) was terminated by signal 6: Aborted
2012-10-02 13:54:30 PDT LOG: aborting startup due to startup process failure
2012-10-02 14:42:49 PDT LOG: database system was interrupted while in recovery at 2012-10-02 13:54:30 PDT
2012-10-02 14:42:49 PDT HINT: This probably means that some data is corrupted and you will have to use the last backup for recovery.
2012-10-02 14:42:49 PDT LOG: database system was not properly shut down; automatic recovery in progress
2012-10-02 14:42:49 PDT LOG: redo starts at A/764C4C0
2012-10-02 14:42:49 PDT PANIC: GIN metapage disappeared
2012-10-02 14:42:49 PDT CONTEXT: xlog redo Update metapage, node: 1663/899422/21182896 blkno: 2
2012-10-02 14:42:49 PDT LOG: startup process (PID 954) was terminated by signal 6: Aborted
2012-10-02 14:42:49 PDT LOG: aborting startup due to startup process failure

I guess it is a problem with an index, because it is saying that there in a GIN metapage missing. Any idea how to get postgres to boot up after it gets into this condition without having to recover from a backup? Would upgrading to 9.2 prevent this issue from happening again?

Thanks,

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Robert Sosinski