Hmm. I'm not sure these errors are related to Spine, but I found some info on how to get rid of them:
https://www.princeton.edu/jcjb/docs/osx_error_fix/
Basically you just do a safe boot, then reboot again. See that link for exactly how, it is easy. You probably want to do this to get rid of those messages even if they aren't related to Spine.
Let's try one more thing. Open Finder, click the Go menu, then choose "Go to Folder" and enter "~/.spine" (without quotes). In the folder that opens, open spine.log and that should contain the errors about why Spine is unable to update.