It's not too tricky to automatically generate an outline flowchart, but things like "CALL $sExternalScript" and so-on mean that it can never be a truly automatic process.

For a really easy way of getting started on a manual solution, comment your script with pseudo-code at decision points and branches. Use a unique phrase (aka a "magic"), something like:

Code:
; #FC# Begin
If InGroup("Administrators")
   ; #FC# User is an administrator - YES
... your code here ...
Else
   ; #FC# User is an administrator - NO
... your code here ...
EndIf
; #FC# End


Once you have been through the script and added these directives you can use "grep" or DOS "FIND" to rip out all the comment lines with the #FC# magic on.

While this is in no way an automated flow-chart tool, it should make the manual process of creating one far easier, and will ensure you don't miss anything.

If your script is simple and linear enough it may even do the job for you.