GoldenGate

We are using Oracle GoldenGate 10.4.0.19(SPARC) on SUN Enterprise Server M5000. The GoldenGate Infrastructure is A->B->C.
Due to configuration problem or version proble, DDL on A can not replicate C. So, we will execute DDL on C before executing DDL on A.
Recently I got the following error about replicate process on C:
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2012-01-19 04:02:38 GGS WARNING 109 Oracle GoldenGate Delivery for Oracle, replc.prm: No unique key is defined for table TIPS_TRD_HKLOG. All viable columns will be used to represent the key, but may not guarantee uniqueness. KEYCOLS may be used to define the key.
2012-01-19 04:02:39 GGS WARNING 109 Oracle GoldenGate Delivery for Oracle, replc.prm: No unique key is defined for table TIPS_TRD_HK. All viable columns will be used to represent the key, but may not guarantee uniqueness. KEYCOLS may be used to define the key.
2012-01-19 04:02:41 GGS WARNING 222 Oracle GoldenGate Delivery for Oracle, replc.prm: Aborted grouped transaction on 'IPS2.TIPS_TRD_HK', Mapping error.
2012-01-19 04:02:41 GGS WARNING 218 Oracle GoldenGate Delivery for Oracle, replc.prm: Repositioning to rba 21054409 in seqno 5193.
2012-01-19 04:02:41 GGS WARNING 162 Oracle GoldenGate Delivery for Oracle, replc.prm: Error mapping from IPS2.TIPS_TRD_HK to IPS2.TIPS_TRD_HK.
2012-01-19 04:02:41 GGS WARNING 218 Oracle GoldenGate Delivery for Oracle, replc.prm: Repositioning to rba 21054409 in seqno 5193.
2012-01-19 04:02:41 GGS ERROR 218 Oracle GoldenGate Delivery for Oracle, replc.prm: Error mapping from IPS2.TIPS_TRD_HK to IPS2.TIPS_TRD_HK.
2012-01-19 04:02:41 GGS ERROR 190 Oracle GoldenGate Delivery for Oracle, replc.prm: PROCESS ABENDING.
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To table IPS2.TIPS_TRD_HK, we found that this table has no primary key or unique. Before about 6 days , the table was added five columns. No other change occurs on this table. The table DDL are same in A,B,C .

After resync this table with data, the replicate process is runing normally. But after some hours, the error occured again.

I don't kown the detail reason. Who can help me ?

Thanks a lot.
Kylix