Question on "mysql replication setup"

Could any one help with the following questions:

In a mysql replication setup, how would you fix the following problems: (All master/slaves running mysql 4.0.18)

1) A slave is reporting (in "SHOW SLAVE STATUS"):
Error 'Duplicate entry '2004-04-07 12:21:17-notepad' for key 1' on query

'UPDATE tbl_name SET date = NOW( )'. Default database: 'asdf'

2) A slave is reporting (in the mysql error log):
040404 13:36:46 Error reading packet from server: Client requested master to start replication from impossible position (server_errno=1236) 040404 13:36:46 Got fatal error 1236: 'Client requested master to start replication from impossible position' from master when reading data from binary log

3) In a master server, InnoDB fails to start with the following error (in the mysql error log): 040327 15:22:25 InnoDB: Page checksum 1278207680,prior-to-4.0.14-form checksum 1577791287
-InnoDB: stored checksum 2893898348, prior-to-4.0.14-form stored checksum 1577791287
-InnoDB: Page lsn 7 638091085, low 4 bytes of lsn at page end 638091085
-InnoDB: Page number (if stored to page already) 818313,
-InnoDB: space id (if created with >= MySQL-4.1.1 and stored already) 0
-InnoDB: Page may be an index page where index id is 0 111
-Ibbackup: Error: page at offset 2 2720153600 in /sql/ibdata2 seems corrupt!