It creates a folder called ${DEFAULTSETTINGSDIR} in my Data folder.
And shouldn't the sumatrapdfprefs.dat go in my Data folder?
EDIT
Yes. It looks like John removed the DEFAULTSETTINGSDIR Variable from the Launcher code but left it in line 142: StrCpy "$SETTINGSDIRECTORY" "$EXEDIR\Data\${DEFAULTSETTINGSDIR}".
Thats why it creates that folder.