Hi

I feel the max size of a datafile is <= 4 GB on windows NT so if you had autoextend on the Temp datafile it is got extended beyond the limit of 4 GB maybe this might be one of the reson as to why it got corrupted I personally dont allow a Temp datafile to extend beyond 4 GB on windows NT.

But Oracle said they fixed this Bug in the later releases of Oracle 8.0.5

Offcourse If you have acces to metalink.oracle.com if you search thru for Ora-01200 you will be able to find more reasons as to what went wrong

Regards