Problem building standalones with substacks in Rev 2.7

[Stgoldberg at aol.com]

Recently, using Revolution 2.7 (I'm not sure if the problem is related to the
version or something else) on my Mac running OS X, I have noted the following
problem in trying to build a standalone:

I first built a main stack, then decided that since I wanted to save data in
the standalone, created a substack to it, and in the Standalone Application
setting, checked off "Move substacks into individual stack files". The
standalone built fine.   However, when I went back and checked off the 
"Create folder
for stackfiles" option (naming the folder "data") the standalone would not
build, instead delivering an error message.   The strange thing is that I 
went
back and unchecked the "Create folder for stackfiles" option and the program
would still not build a standalone.   I've repeated this several times to be 
sure
that this is where the problem arose.   Can anyone suggest what may be the
problem?   I've made sure to name the stack, substack, and folder 
differently.

Perhaps it may relate to the fact that I originally created two mainstacks,
and then set one stack as the main stack through the command "set the 
mainstack
of stack 'B' to 'A'   but I have not experienced this difficulty before   in
rev 2.6 using the same command.   Again, the problem may not relate to the
version, but to something I'm doing wrong.

In addition, I've note that under rev 2.7, when one builds a standalone,
there is a separate folder created in the Windows folder titled 
"Externals".  
What is that for?   Thanks.
Steve Goldberg