🚀 go-pugleaf

I'm having problems with MSC 6.0 intermittently not finding include
files along the include path.  This usually occurs when making from
inside of Epsilon 5.0, but occasionally occurs on the command line.
The compiler exits with "Fatal error C1024 cannot open include file
'file'".  The include file is always a nested file (ie. it's included
by another include file). Here's the include path:

set INCLUDE=E:\C600\INCLUDE;.;E:\U\PRJ2\INCLUDE

Both the main include file and the nested include file are in the
last directory. It doesn't seem to matter whether I use quotes or
angle brackets around the include file name.
 
I'm running a dual-boot/Multiboot system with DOS, OS/2 1.3, and OS/2
2.0 on a PS/2 Model 95. (The DOS and 1.3 systems are set up as dual
boot, occupying one position on the Multiboot menu, with 2.0 taking
the second position.)  This problem usually happens in 2.0, less
frequently in 1.3.

Can someone tell me what's going on and what I need to do to fix it?
It's terribly frustating to have to leave the editor to compile,
especially when it means I have to chase errors manually rather than
letting the editor automagically position to them.  It's even more
frustrating when the problem starts occurring on the command line and
I have to switch to the other OS version to get relief.  I live in
fear of the problem happening simultaneously under both versions.

Ken