error occured in dbt2 against with postgresql

*$ dbt2-run-workload -a pgsql -d 10 -w 1 -c 1 -o
/home/store/tmp/testdbt2/out-1.o*
postmaster starting
DBT-2 test for pgsql started...

DATABASE SYSTEM: localhost
DATABASE NAME: dbt2
DATABASE CONNECTIONS: 1
TERMINAL THREADS: 10
TERMINALS PER WAREHOUSE: 10
WAREHOUSES PER THREAD/CLIENT PAIR: 500
SCALE FACTOR (WAREHOUSES): 1
DURATION OF TEST (in sec): 10
1 client stared every 1000 millisecond(s)

Stage 1. Starting up client...
Sleeping 501 seconds
collecting database statistics...

Stage 2. Starting up driver...
1000 threads started per millisecond
estimated rampup time: Sleeping 5010 seconds

estimated rampup time has elapsed
estimated steady state time: Sleeping 10 seconds

Stage 3. Processing of results...
Killing client...
/usr/local/bin/dbt2-run-workload: line 518: 24055 Terminated
dbt2-client ${CLIENT_COMMAND_ARGS} -p ${PORT} -o ${CDIR} >
${CLIENT_OUTPUT_DIR}/`hostname`/client-${SEG}.out 2>&1
waiting for postmaster to shut down.... done
postmaster stopped
*Can't use an undefined value as an ARRAY reference at
/usr/lib/perl5/site_perl/5.8.8/Test/Parser/Dbt2.pm line 521.*
The authenticity of host 'localhost (127.0.0.1)' can't be established.
RSA key fingerprint is b6:da:1d:d0:28:d7:ed:06:08:72:44:de:02:f1:b9:52.
Are you sure you want to continue connecting (yes/no)?
Host key verification failed.
Test completed.
Results are in: /home/store/tmp/testdbt2/out-1.o

Response Time (s)
Transaction % Average : 90th % Total
Rollbacks %
------------ ----- --------------------- ----------- ---------------
-----

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Best regards,
Niu Yan