was getting the following error after installing php 5.2.6 on IIS with IIS CGI configuration:

PHP Warning: PHP Startup: Unable to load dynamic library 'C:\Program Files\PHP\ext\php_pgsql.dll' - The specified module could not be found. in Unknown on line 0

I resolved this by replacing the .dll in this location with my .dll from a previous install (php 5.2.5) ... you can probably use the .dll from any version