make sure postgreSQL runs:
1) Windows Start Button => Programs => Postgre SQL 8.3 => start service
2) give elpehant correct name/pass for your postgre Installation.
If nothing helps, please try reinstalling postgre SQL through this manual:
Please delete PostgreSQL completly through this:
0) Deinstall PostgreSQl thought your normal windows deinstallation process
1) Download this file (DONT CLICK IT!)
http://www.pokerstrategy.com/download/content/elephant/pt2_elephant/Remove_PostgreSQL_Total.zip
2) Rightclick this file => edit with wordpad/editor
3) edit the field "postgres" with the user you choosed to create through your postgreSQL installation. NEVER EVER USE YOUR OWN ACCOUNT!
it has to be the elelpehant/postgresql account.

4) Save the file, rightclick it, and run as admin. If this option is not shown, just double click it.
5) Postgre SQL is now completly removed.
Now try a fresh installation of postgreSQL, this error should not happen again.