Exchange 5.5 error

We keep getting this error MSExchangeIS (422) Online defragmentation of database ‘D:\exchsrvr\MDBDATA\PRIV.EDB’ terminated prematurely after encountering unexpected error -1019 in our event logs. We have ran all the utilities that Microsoft has recommended. What is the best thing to do to fix this error. I would like to fix it before we upgrade to Exchange 2000. The Exchange 5.5 has the latest service packs and so does our Nt4.0. Any help would be appreciated.