Autentication exceptions in pgsql 8.3

Hello,

I am using Postgresql 8.3, I am getting the below authentication
exceptions. I am not able to connect using
postgres://mpp:mpp(at)localhost/mpp

LOG: provided username (mpp) and authenticated username
([U2FsdGVkX1/4XrEZ3dfREbh66kqWj66oEZjvotlVtqo=]) don't match
FATAL: Ident authentication failed for user "mpp"
LOG: provided username (mpp) and authenticated username
([U2FsdGVkX19aYlj8eW0BPmAZ4Loziuy64Urcd4ZhMOg=]) don't match

Here is my contents in pg_ident.conf

# MAPNAME SYSTEM-USERNAME PG-USERNAME
mpp mpp mpp

Here are my contents in pg_hba.conf

# TYPE DATABASE USER CIDR-ADDRESS METHOD

# "local" is for Unix domain socket connections only
local all postgres ident
local all mpp ident
local all mppadmin ident
local all all ident

# IPv4 local connections:
host all all 127.0.0.1/32 ident
# IPv6 local connections:
host all all ::1/128 ident

I tried adding the map and key value too but it did not help.
Please help to resolve this issue.

Thanks and Regards,
Deepthi