This is not a duplicate of this same issue, which was marked as fixed, since this is on a newer version.

The attached save file produces te attached crash report. Sometimes immediately, sometimes after flying around a bit.
The save file is of a custom map made with WorldPainter, but it should work normally (and does load and is playable for a while).
The crash report says n must be positive, referring an argument to Random.NextInt.

There are several issues closed for this same crash and it's considered fixed, but it is still happening on 1.7.4 and on the latest snapshot.

Thanks for the hard work. =3