Errors from pgbench

I ran pgbench like so (8.1.4 on x86-64):

$ ./bin/pgbench -s 100 -i pgbench

$ ./bin/pgbench -t 100000 -c 10 pgbench
starting vacuum...end.
Client 9 aborted in state 8: ERROR: integer out of range
Client 5 aborted in state 8: ERROR: integer out of range
Client 8 aborted in state 8: ERROR: integer out of range
Client 4 aborted in state 8: ERROR: integer out of range
Client 1 aborted in state 8: ERROR: integer out of range
Client 3 aborted in state 8: ERROR: integer out of range
Client 0 aborted in state 8: ERROR: integer out of range
Client 2 aborted in state 8: ERROR: integer out of range
Client 7 aborted in state 8: ERROR: integer out of range
Client 6 aborted in state 8: ERROR: integer out of range
transaction type: TPC-B (sort of)
scaling factor: 100
number of clients: 10
number of transactions per client: 100000
number of transactions actually processed: 384423/1000000
tps = 239.586507 (including connections establishing)
tps = 239.589618 (excluding connections establishing)

The only way I see to generate that type of error is if it tried to
insert or cast an integer too large for the data type.

Is this a potential pgbench bug, or am I misusing pgbench?

Regards,
Jeff Davis