The program can’t start because LIBPQ.dll is missing from your computer. Try reinstalling the program to fix this problem.
If you’re getting the above error when starting Apache after installing Apache and PHP on your Windows machine, go to your PHP install directory (e.g. c:Program Files (x86)PHP) and copy the file libpq.dll into the bin directory under the Apache install directory (e.g. C:Program Files (x86)Apache Software FoundationApache2.2bin).