There is no built-in command to do a delay in MSI script in WPS 4.0 and below. Obtain a program called Scriptnap.exe from the Internet. It was designed for this exact purpose.
-Copy this file to the C:\Program Files\Wise Package Studio\Windows Installer Editor\Resources folder
-Go to the MSI Script view:
-Select the Execute Deferred page
-Place it after the InstallFiles action (or wherever you need the delay)
-In the left column select Execute Program From Installation
-Custom Action Name: Delay
-Executable file: <browse to Scriptnap.exe>
-Click Ok
-Save the WSI
-In the Installation Expert view while in your WSI:
-Go to Product Definition section select Resources
-Click add
-Name: CallScriptnap
-Filename: [WisePath]\Resources\Scriptnap.exe
-Click Ok
-Check the refresh box for the CallScriptnap resource
-Save the WSI