Package issue

Really want to refactor and re-architect my project, it's become basically an 11k line monobloc that desperately needs to be split into multiple classes (and class files) inside a single package.

Yes I know I should have figured all this out when I started, but this is play not work and I was brand new to AS3 when I started. And I've kept building and building and it all works, it's just become very hard to manage.

My immediate goal is to define a package and then start breaking out function groups from the current main class into subclasses that extend the base. But I'm having a problem with the first step - defining the package.

I'm getting:

C:\Users\Vossie\Documents\Fex Line of Battle Project\trunk\line_of_battle\LOB_Core.as, Line 1, Column 1 5001: The name of package 'line_of_battle' does not reflect the location of this file. Please change the package definition's name inside this file, or move the file. C:\Users\Vossie\Documents\Fex Line of Battle Project\trunk\line_of_battle\LOB_Core.as

So I've checked:

package line_of_battle {
public class LOB_Core extends flash.display.MovieClip {

Filename is LOB_Core.as.

Path:

Class path:

Such a simple thing but I must be missing something since I keep getting the same error. I even created a new folder in a new location and created new test package parent class and child class with all new names carefully checked, and I get the exact same error. It keeps insisting my package name doesn't agree with the folder name even though that is clearly not the case.