Php can't find PostgreSQL library allthough it exists in the specified folder

I try to install postgresql server in combination with Xampp's components.

First i installed PostgreSQL with his installer.

Then i've changed in the php.ini

extension=php_pgsql.dll

as next i wanted to restart my apache server but i get the error:

PHP Startup: Unable to load dynamic library "C:\xampp\php\ext\php_pgsql.dll". The specified module couldn't be found.

But there exists the file C:\xampp\php\ext\php_pgsql.dll in the right location...

Any ideas, how i can fix this problem?

Thank you very much

On a Windows server, configured with Apache, adding the following line to httpd.conf to load libpq.dll can solve the problem:

LoadFile "C:/Program Files/PostgreSQL/8.4/bin/libpq.dll"

Use the appropriate version of php_pgsql.dll - the version that is compiled for your current php parser.