Novice Houdini user with an active Indie subscription

This may be a License administrator issue.

I can launch and run Houdini (Windows 10) no problem via a shortcut on my desktop.

However, when trying to install any Orbolt asset the Orbolt install executable launches my license administrator.

My license administrator tells me that I cannot modify license from this machine and the install quits.

Can anyone help?

It may simply be reporting the truth. Each asset on Orbolt has a required license. An Indie license may not be enough for the asset you have chosen. Contact the asset developer or re-read the license requirement for the asset on Orbolt.

Have you tried simply copying the .otl file directly into your Store/Assets folder? Typically found under My Documents/ Houdini 15.x/…
Once copied to the folder you can reference it into your scene via File/Import/Houdini Digital Asset.

Try something free like the Equalizer from SideFX, it has a completely open license.