PGSQL 8.1.4 on Win2003 at istanbul :), could not access status of transaction xxxxx , could not open file "pg_subtrans/000A": Invalid argument

Hi
There is a new installed PostgreSQL 8.1.4 running on Windows2003.
Last 3 days we get error message below incidentally. After first error, we
get the error frequently.
After restart the service, the error gone.

2006-07-13 19:43:57.218  192.168.3.14(1093) test user SELECTLOG:  duration:
15.000 ms  statement: select * from personaldetails where masterid=215
2006-07-13 19:43:57.234  192.168.3.14(1093) test user SELECTERROR:  could
not access status of transaction 679109
2006-07-13 19:43:57.234  192.168.3.14(1093) test user SELECTDETAIL:  could
not open file "pg_subtrans/000A": Invalid argument
2006-07-13 19:43:57.250  192.168.3.12(1048)  test user2 SELECTLOG: duration:
63.000 ms  statement: select id,dueamount(id),payment(id),allocatedtotal
id),balance(id) from personaldetails where id =1142 limit 1



Regards,
Ali �EL�K