RDBMS Conversion - error/warning

While doing RDBMS conversion for an Particular table, getting an warning/error as "A68005 record key data error, key is null value" (shown below).
End result is fine i.e. table is successfully converted to Oracle. But Needed to know the reason of the below error. Please advice.
jsh test ~ -->CT ./temvijay/rdbmsConversion/DataErrors
F.BM.HOLD.CONTROL
001 A68005 record key data error, key is null value
002 null key ''
003 XMLORACLE
004
005 F_BM_HOLD_CONTROL
006 NOXMLSCHEMA=YES
007
008
009
010
011
012
013
014 ../bnk.dict/F_BM_HOLD_CONTROL]D
015 ../bnk.rdbmsdict/F_BM_HOLD_CONTROL
016
017 DICT
018 J4
019
020
021 J4
022
023 0
024 TABLE
025 F.BM.HOLD.CONTROL
026 0