BUG #15639: Unable to connect to database with dsn dbi

The following bug has been logged on the website:

Bug reference: 15639
Logged by: Ding Linda
Email address: linda(dot)ding(at)cemtek(dot)com(dot)cn
PostgreSQL version: Unsupported/Unknown
Operating system: Linux
Description:

I run into a problem with the postgresql server. Is there any way to remove
it separately and do a clean install of Postgresql only?
Here’s one of the error messages I get:

Unable to connect to database with dsn
dbi:Pg:dbname=pmx_quarantine;port=5432;host=mgate2.cemtek.com.cn.cemtek.com.cn:
DBI
connect('dbname=pmx_quarantine;port=5432;host=mgate2.cemtek.com.cn.cemtek.com.cn','',...)
failed: FATAL: no pg_hba.conf entry for host "117.184.46.144", user "pmx6",
database "pmx_quarantine", SSL on
FATAL: no pg_hba.conf entry for host "117.184.46.144", user "pmx6", database
"pmx_quarantine", SSL off at
/opt/pmx6/lib/site_perl/5.8.7/PureMessage/Reports/Reductor.pm line 67
at /opt/pmx6/bin/pmx-prd-reduce line 46

and also

/opt/pmx6/postgres/bin/pg_ctl: error while loading shared libraries:
libpq.so.5: cannot open shared object file: No such file or directory
when I try to start the server manually.

Apparently something went wrong during the pgsql installation and I’m not
sure how to fix the host problem and add the missing LD_LIBRARY_PATH
variable.