You must ensure Web Platform Installer version should be same on the server where you are downloading Workflow Manager 1.0 files and on the server where you are installing Workflow Manager 1.0 files for offline installation scenarios.

As I was following Spencer Harbar’s workflow manager 1.0 installation guide for offline installation, I came across following error while triggering offline Workflow Manager 1.0 installation process using Windows PowerShell.

Windows PowerShell
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PS C:\Windows\system32> cd "c:\WorkflowManagerFiles\bin"
PS C:\WorkflowManagerFiles\bin> Webpicmd.exe /Install /Products:WorkflowManager/XML:C:/WorkflowManagerFiles/feeds/latest/webproductlist.xml

The software that you obtain using the Web Plaform Installer Command Line Tool is licensed to you by its owner.  Microsoft grants you no rights for third party software.
Unexpected exception occurred
An installer element must contain either a child iisComponent element, an installCommands element or an msDeploy element. Line 30928, position 8.
PS C:\WorkflowManagerFiles\bin>

As it turned out, I have downloaded workflow manager files using most recent Microsoft Web Platform Installer 4.6 and the Workflow server (Windows Server 2008 R2) where I was trying to install workflow manager files had Web Platform Installer 4.0 installed.

Windows Server 2008 R2 Server with Web Platform Installer 4.0

After downloading and installing latest version of Web Platform Installer (v4.6) on the workflow server, I was able to trigger Workflow Manager offline installation using PowerShell successfully.

The reason I have blogged this article is error message is not descriptive enough to explain why workflow manager installation process failed due to web platform installer version differences. I ended up spending few hours before coming across this article which gave me hint of version differences. Hopefully it would save some time for others.