When processing a block in the specified redo log file, the PowerExchange Express CDC for Oracle log reader encountered unexpected block number and sequence number values in the block header. An internal processing error might have occurred, or the log file might be corrupted. In an Oracle RAC environment, this message includes the name of the relevant RAC member.
The log reader tries to use the alternate log file that has the same sequence number. If this alternate log file does not exist, CDC processing ends.