This isn't much to go on, but it sounds like there's something wrong with your build.
There's a lot of mentions of Spine.Unity.SkeletonDataAsset and Spine.Unity.AtlasAsset in there but also whole a bunch of other asset types.
It doesn't look like it's Spine-specific.
You may also have to try asking in the Unity forums to see what they have on it. Just the editor log file may not be enough information for them though. You may have to share your build settings, target, version, plugins you're using, etc...