!verbose: Pop failed Warnings

I've recently upgraded my PC.
I was on Win7 32bit, using makensis version 2.46.
Now on Win8 64bit, makensis version 3.0a2.

I'm compiling the exact same code (copied from old PC to new).
I'm getting compiler warnings:

warning: !verbose: Pop failed, stack is empty (macro:MUI_INSTALLOPTIONS_EXTRACT:7)

I get 6 of these errors, one for each line including an options page in .onInit, e.g.:

!insertmacro MUI_INSTALLOPTIONS_EXTRACT "InstallType.ini"

Clicking the error in the editor takes me to the macro in System.nsh, which I assume is included by MUI.nsh.

I know the compiler is telling me that the stack is empty when trying to pop, but the pop its showing me is done by !macro MUI_INSTALLOPTIONS_EXTRACT FILE, and its after !verbose push so I don't understand how the stack could be empty.

The script compiles and creates an installer which appears to be working, but I'd rather not have compiler warnings, obviously something is wrong somewhere.

Can anyone point me in the right direction?
Many thanks, Brad.

INSTALLOPTIONS_EXTRACT has a pop that does not belong there, I already fixed this in trunk here

Thank you for the quick reply Anders.
Glad I wasn't doing something totally wrong.