Thanks for the report!
What I can gather from your error log is that the object which is calling the "execute after 60 frames" was deleted/destroyed in the meantime? I thought I caught all errors of that type, but I might have missed a checked somewhere. I will look into it and update when I find the error.
It would be really helpful if you could share your project with me, so I can debug it faster (you can also create a new project that reproduces the same bug). You can reach me via ribbyteapps at-symbol gmail.com
If you find any more bugs, feel free to report all of them.