This is what I did to get to this result.
I installed Qt Creator and tried to build / run some of the examples.
Then I opened the plugandpaintplugins project and tried to compile this. This is where I got these errors.
I am testing on a Win XP platform, where also a copy of Visual Studio 2003 .Net is installed.
In the mean time I have done some more research, and found out that there might be a conflict between a Visual Studio 2003 installation and Qt Creator. I removed the include and lib environment variables (refering to C:\Program Files\Microsoft Visual Studio .NET 2003\SDK\v1.1\include\ and to C:\Program Files\Microsoft Visual Studio .NET 2003\SDK\v1.1\Lib\) and now I can build the plugins.

regards,
Jan