Latest Snapshot Broken

My brother gets this error every time he tries to use the snapshots. Im not sure whats going on. I removed all resource packs and mods that we had, even if we didn't use them. Yet it still wont work. Im not sure how to read these bug crashes so I have no idea what its telling me the problem is. I wouldent have reported this here but dont know anywhere else to report this. This is more of a casual, non urgent issue.