Build Error: C:\Qt\2009.05\mingw\bin\mingw32-make.exe: Interrupt/Exception caught (code = 0xc0000005, addr = 0x41f96e)

(I presume your addresses may vary, and I was building the "textobject" sample from the Getting Started screen.)
More text from the build error:

Running build steps for project textobject...

Starting: c:/qt/2009.05/qt/bin/qmake.exe C:/Qt/2009.05/qt/examples/richtext/textobject/textobject.pro -spec win32-g++ -r

Exited with code 0.

Starting: C:/Qt/2009.05/mingw/bin/mingw32-make.exe -w

mingw32-make: Entering directory `C:/Qt/2009.05/qt/examples/richtext/textobject'

C:/Qt/2009.05/mingw/bin/mingw32-make -f Makefile.Debug all

C:\Qt\2009.05\mingw\bin\mingw32-make.exe: Interrupt/Exception caught (code = 0xc0000005, addr = 0x41f96e)

Exited with code 255.

Error while building project textobject

When executing build step 'Make'

This happens because the installer for the MinGW Windows release 2009.05 doesn't set the PATH environment variable. Qt cannot find the MingGW tools.
 
Here's a bug: http://bugreports.qt.nokia.com/browse/QTCREATORBUG-517
 
right-click My Computer->Properties->Advanced->Environment Variables
in the upper box, if Path doesn't exist, add Path and set it to:
c:\qt\2009.05\mingw\bin;C:\Qt\2009.05\qt\bin

Or, if Path exists, double-click on it, append a semicolon, then append that string. Also, note your installation. If you install Qt after then next release, it may install in the "2010.01" directory or something similar.

Build->Rebuild All now gives me a green bar under "Build"--Success.