Help! Backend crashed with status 139 ( may be long SQL query)

Hello all.

When i had tried to insert into text field text (length about 4000 chars), the backend have crashed with status 139.
Thiserror is happened when the query length ( SQL query) is more than 4095 chars. 
I am using PostgreSQL 6.4.2 on Linux.

My questions are:
1. Is there problem with text field or with length of SQL query?
2. Would postgresql have any limits for SQL query length?

Thanks for help
                    Natalya Makushina
                    mak@rtsoft.msk.ru