/tmp is indeed supposed to be 777. everybody has to have a guaranteed writable location, and /tmp is it. That’s what it’s for.
As far as resource not available, what version are you running? Sounds like a leak in something… memory? File handles? Something.
There were some leaks that were fixed in the last couple nightlies. The latest nightly should be (??) relatively leak free, though. So if that’s what you were running, then something is indeed screwy.