It's pretty simple, you should change this line:
Code:
reg add HKLM\SYSTEM\CurrentControlSet\Services\impserve\Parameters /v AppParameters /d "-l \"%~dp0\impserve.log\"" /f
to
Code:
reg add HKLM\SYSTEM\CurrentControlSet\Services\impserve\Parameters /v AppParameters /d "\"YOURDIRGOESHERE\" -l \"%~dp0\impserve.log\"" /f
The \" is required as the directory in which you install may have spaces...