I used the steps as outlined in the post http://forums.scummvm.org/viewtopic.php?p=27646#27646
Maybe there was a mistake in the batch files, but I've no idea how to fix it

When I execute convert_dxa.bat that's what I see:
Setting environment variables...
Processing D:\games\FeebleFiles\XXX.smk"...
Width: 640, Height: 480, Framerate: 10000, Frames = 2720
Encoding video... read_png_file: Can't open file: XXX00.png
And that's all. It just deletes .smk files from the game folder and puts very strange unworking .dxa files into scummvm tools folder, they're all the suspicious size (19 bytes each), so I guess the conversion never really happens...
What's wrong?
That's how the batch files look:
convert_dxa.bat
@echo off
rem Feeble Files smk->dxa batch convertor
echo Setting environment variables...
SET TOOLS_PATH=D:\games\scummvm\tools
SET BINK_PATH=D:\Program Files\RADVideo
SET SMK_PATH=D:\games\FeebleFiles
SET DXA_PATH=D:\games\FeebleFiles\dxa
for %%i in (%SMK_PATH%\*.smk) do call convert_dxa2.bat "%%i"
echo Converting finished!
convert_dxa2.bat
@echo off
echo Processing %1...
"%BINK_PATH%\BinkConv.exe" %1 "%SMK_PATH%\%~n1.png" /n-1 /z1 /#
"%BINK_PATH%\BinkConv.exe" %1 "%SMK_PATH%\%~n1.wav" /v /#
"%TOOLS_PATH%\encode_dxa.exe" "%SMK_PATH%\%~n1.smk
echo Deleting temp files
del "%SMK_PATH%\%~n1*.png"
del "%SMK_PATH%\%~n1.wav"
move "%SMK_PATH%\%~n1.*" "%DXA_PATH%"