pg_hba.conf

I have a machine with Linux/PostgreSQL in my local network with ip
192.168.1.10
I tryed to conect from another machine (192.168.1.3) with pgaccess
I got a message error: no entry for 192.168.1.3 db x user y..etc...in
pg_hba.conf

I tryed to put a line in pg_hba.conf to allow this, and did not work, so I
removed that line.
After that I can not even conect from the back-end machine (192.168.1.10)
the message is that: "missing or erroneous pg_hba.conf file"

Any direction please ?

Eduardo K