Minecraft.exe is just the launcher. The path needs to be to your minecraft.jar file. If you're using Windows 7 the path would be C:\Users\Paul\AppData\Roaming\.minecraft\bin, except you need to substitute whatever your username is instead of "Paul". Try changing it to javaw -Xmx750m -Xms375m -jar "C:\Users\Gabriel\AppData\Roaming\.minecraft\bin\minecraft.jar"
I got XP Home Edition. EDIT: I did this and I received the same problem except with the new direction.
Yes you can use a batch file but what i did is make a shortcut with the location as: "C:\Windows\System32\javaw.exe -Xmx750m -Xms375m -jar "C:\Users\Gabriel\Desktop\Minecraft.exe" On mine, i have the location as C:\Windows\System32\javaw.exe -Xmx5G -Xms5G -jar "C:\Users\Tyler\Documents\Minecraft.exe"