ORA-00600: internal error code, arguments: , , , , , , , 
Oracle Version: 8.1.7
we have encounter the above error and the DB stop responding at all. Could anyone help us and give us any idea whether it is hardware or software problem?
From Metalink: The ORA-600  indicates Undo record number mismatch while adding an undo record to an undo block.
Most of the solutions I read indicate you need to recover to a point in time before this happened, or restore from cold back up if you are not archivelogging. In many cases, the recommendation from Oracle is to log a tar with them and have them work through the problem with you.
From what I've read, it sounds like it could be some file corruption problems... but it is tough to call being so removed from the actual problem.