Program lose the connection to backend

I have a program thar reads a file with a lot of rows (10000) and, sometimes, 
my program can't insert new rows to the database because it lost the 
connection to the backend. The problem is random and I don't know what 
happens.

This occurs also sometimes when I run a big query or  VACUUM. SOMETIMES.

I'm using Postgres 7.1.2 and 7.2.

I think that postgres 7.2 slower than 7.1.2. My program processed 650 files 4 
times faster in 7.1.2 using the same database structure (created by pg_dump 
-s). Is this true? Is 7.2 slower?

Thank a lot,

-- 
Ricardo Vaz Mannrich
Linux user: #158685