Vitrop

I'm having issues with starting my mod. I'm new to modding and followed this tutorial on youtube and keep getting a error at the very end on a Process 'command 'c:\program Files\Java\jdk1.8.0_211\bin\java.exe' ' finished with non-zero exit value -1 not really sure how to fix it. I've looked through forums on here for like 2 hours but couldn't find anything to help. Anyone got any ideas or a link to a similar forum.