Hi,
>>"I have been using the Layiso and Layon command for many years."
Familiar with Layiso, okay.
>>"Suddenly, after typing this command, all layers become locked."
Suddenly? It should lock your layers (dependent your setting) after ending the object selection,
not suddenly after typing this command.
Please test it again.
>>"I tried to select settings on the layiso command line to turn VPfreeze off and Lockandfade to off..."
And? Does it work or not?
Start LAYISO command, walk thru setting option.
Is it set to off or not, use Off. Is vpfreeze on or off?
You started the right command? Sorry that I am asking this, but sometimes, everyone make a mistake.
It's a possible problem, so I ask for.
>>"but all layers remain locked."
Sure, it's on you to unlock layers.
>>"I attached a screen shot below."
>>"I tried to manually un-lock all of the layers but they become locked again after closing the layer state drop-down"
We can see the UNDO statement.
And if you use the Layerproperties-palette, which is almost the muchg better choice for this task?
Or command line:
-LAYER _unl *

From fresh
1. Restart the program, open the file and set your layers like you want.
2. Check Layiso settings again
3. Try it again.
Still a problem?