Not being able to start Calligra apps

[Jörg Knobloch]

Following
https://community.kde.org/Calligra/Building_Calligra_on_Windows
I managed to build some Calligra apps based on KDE 4.13.

I built KDE into c:\kderoot and Calligra into c:\kde4.

I prepared a batch file as follows:
kde.bat
===
@set KDEDIRS=c:\kderoot
@set KDEROOT=c:\kderoot

@set KDEDIRS=c:\kde4\inst;%KDEDIRS%
@set PATH=c:\kde4\install\bin;%PATH%
@set PATH=c:\kderoot\bin;%PATH%
@set KDEHOME=%USERPROFILE%\kde4\.kde
===

This is what happens when I try to run a Calligra app:

C:\kde4>kde.bat

C:\kde4>kbuildsycoca4
kbuildsycoca4 running...

C:\kde4>inst\bin\calligrawords.exe -v

C:\kde4>Qt: 4.8.5
KDE Development Platform: 4.13.3
Calligra Words: 2.8.5

C:\kde4>inst\bin\calligrawords.exe

C:\kde4>Warning: QFileInfo::absolutePath: Constructed with empty filename
Warning: QFileInfo::absolutePath: Constructed with empty filename
Warning: QFileInfo::absolutePath: Constructed with empty filename
Warning: QFileInfo::absolutePath: Constructed with empty filename
Warning: QFileInfo::absolutePath: Constructed with empty filename
[more identical messages follow]

[The application frame flashes up briefly and closes again.]

Same behaviour for calligraauthor.exe and calligraflow.exe.

I noticed that the following process get started:
c:\kderoot\bin\kde4.exe
c:\kderoot\bin\klauncher.exe
c:\kderoot\bin\dbus-daemon.exe

Also, every time I try to start a Calligra app I get the warning that 
I'm running a 32 bit app on a 64 bit system. That shouldn't matter, 
should it?

Any hints?