Expanded Mode, Segments and Invalid Pointers

I am trying to clean up the amount of globals in an app and am 
getting invalid pointer notes in the CodeWarrior debugger watch 
window for quite a few Char*. They are declared globally and memory is allocated
in the init of the main form. During debug, after the 
memory is allocated they still show as invalid pointers and when trying to place
content at the pointer using StrCopy, the app crashes.

Noteworthy: This is after trying to clean up globals and changing 
where variables are declared as extern. I also switched to expanded 
mode which seems to get around a link error I was getting (__RuntimeModule__:
Near data segment is bigger than 64k). In the CodeWarrior 9 Segment tab of the
debug target, the Code column says 66K for Segment_1.

I am unsure of the benefits and purpose of expanded mode and havne't found much
for a real explanation. Ben Combee used to have 
a link to a white paper on it but I didn't read up or try to use it till now and
the link is broken. Can anyone help me piece this together?