macrium error message: cannot clone volume while Windows is running

Question

I want to clone my 128GB SSD boot drive to a 512GB SSD.

I open Macrium Reflect inside Windows 7 x64. When I identify the source and target drives, and eventually get to the point where I tell Macrium to proceed with the cloning, Macrium says it cannot complete the operation while Windows is running. It says to boot from the PE repair disk.

So I boot from the PE repair disk, which brings up a Macrium splash screen with menu options. But reflect.exe cannot be run from the PE command line. I get an error message that oledlg.dll is missing.

All of the online videos showing how to clone a drive show Macrium already running, so I don't know where it has been booted from.

I'd be grateful for some advice.