need help on my postgres on centos 4.3

I am totally new to postgres and need help to fix a problem comes from
rake command. This morning I installed postgres 8.2 on my centos 4.3

the steps I used to install postgres are as follows:

1) wget postgresql-8.2.2.tar.gz from
2) tar -zxf postgresql-8.2.2.tar.gz
3) yum install flex
4) ./configure --prefix=/usr/local/pgsql --without-readline
5) gmake
6) gmake install
7) export POSTGRES_INCLUDE=/usr/local/pgsql/include/
8) export POSTGRES_LIB=/usr/local/pgsql/lib/
9) export LD_LIBRARY_PATH=/usr/local/pgsql/lib/
10)gem install ruby-postgres

everything was fine. after that, I started postgresql and created a test


it was ok too.

then, rails test --database=postgresql

it was successfully as well.

when I test rake db:migrate, I got the following error message:

(in /usr/local/html/test)
rake aborted! cannot open shared object file: No such file or directory -

I found is located at folder ruby-postgres-,
no idea why there is a "./" before any one could help me
out? thanks.