Problems when inserting a very large sequence of records

I am experiencing a problem when I was inserting a lot of records to one
table.

At the end of process (I was insering about 15,000 lines) after the COMMIT
statement some
records were not stored.  No error messages, no warnings.  If  I decrease
the number of inserted lines to 1,500 they are stored.

Do you know what is happening ?

Note: I am using RedHat Lynux, Postgresql version 7.3 on a Windows Me client
machine with odbc version 7.0.7.  I connect to postgresql using ODBC API
fuctions.


Thanks.

Marcelo. ( São Paulo, Brazil).