I have solved the problem! See the original post, "A strange problem with modeless dialog boxes", for details.
This is a repost, incorporating the latest simplifications of the problem statement, and a minimal reproducible example of the code...
I'm having a problem with modeless dialog boxes...
application
c++
code optimization
debugging
dialog boxes
event handling
file scanning
graphics
gui
linked list
modeless
multi-threading
performance
progress bar
sleep function
systemcalls
timers
user interface
window procedure
windows development
The statvfs() call in SUA may fail with the following error on a Windows 7 or Windows Server 2008 R2 based system: statvfs(): errno = 88 (Value too large to be stored in data type)
Link Removed
When I rebooted my computer this AM a number of icons on the desktop had been replaced with the windows default icon used when Windows can't find the icon specified.
Also, I could not access a number of root folders and the programs in them would not run from system calls as in the startup...