could not send data to client: Broken pipe

Hi;
Hope somebody can help to figure out my problem.
When I run this sentence manually "psql -U user -d db_name -f /
script.sql" , It runs perfectly.(4033 rows are inserted).
Yet, when I run it using crontab, Only 77 rows are inserted.

when I see the postgres Log, it shows me this after row 77
....
2009-09-16 09:57:01 AST LOG:  could not send data to client: Broken
pipe
2009-09-16 09:57:01 AST LOG:  unexpected EOF on client connection


Thanks a lot for your help