sgs2toext4.jar not working on Windows 7 32 bit

[Johny]

Hello, I want to unpack the system.img, to do it needs to convert it to ext4 format, I always did it using the sgs2toext4.jar program and there was no problem until I changed RAM, now when I upload the system.img file to sgs2toext4 it's okay does not happen, it always shows 0% kBs. Does anyone know a solution