These are the changes I made to get it to work.
:: Change this only! Must be the same as the subfolder name
@Set mod=Ergo's_Fixpack
:: sub-folder where the SQL-files can be found
@Set mod=Ergo's_Fixpack
::--------------------------------------------------------------
:: Nothing needs to be changed below
::--------------------------------------------------------------
@echo off
echo.
set pfad=.
if not exist %pfad%\static.db4 FOR /F "tokens=2* " %%A IN ('REG QUERY "HKCU\Software\DTP\Drakensang" /v target_folder') DO SET Pfad=%%B\export\db
if exist %pfad%\static.db4 goto okay
Echo The path to "Drakensang\export\db\static.db4"
Echo couldn't be read from the Registry!
Echo.
Echo To install, please copy all the mod's files and folders
Echo to the folder "Drakensang\export\db\", and start
Echo "Install-English.bat" again there.
Goto End

kay
FOR /F "tokens=2* " %%A IN ('REG QUERY "HKCU\Software\DTP\Drakensang" /v version') DO SET version=%%B
Echo Drakensang v%version%
Echo Datenbank-Directory = "%pfad%"
echo.
echo.
echo Creating backups...
if not exist %pfad%\static.db4.(%version%)%backup% copy %pfad%\static.db4 %pfad%\static.db4.(%version%)%backup%
if not exist %pfad%\locale.db4.(%version%)%backup% copy %pfad%\locale.db4 %pfad%\locale.db4.(%version%)%backup%
if not exist %pfad%\game.db4.(%version%)%backup% copy %pfad%\game.db4 %pfad%\game.db4.(%version%)%backup%
echo.
echo Updating %pfad%\static.db4...
%mod%\sqlite3 %pfad%\static.db4<%mod%\static.sql
echo.
echo Updating %pfad%\locale.db4...
%mod%\sqlite3 %pfad%\locale.db4<%mod%\locale.sql
echo.
echo Updating %pfad%\game.db4...
%mod%\sqlite3 %pfad%\game.db4<%mod%\game.sql
echo.
echo Copying new icons...
mkdir %dsroot%\textures\icons
copy %mod%\textures\icons\*.* %dsroot%\textures\icons /Y
echo.
echo.
Echo Installation finished.
:End
echo.
pause