MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
See my comment here: https://www.thingiverse.com/thing:3413943/comments/#comment-2334392
I, personally, am happy to remove it, but I'm not sure it's that simple.
As for the little hearts, these were modelled separately but all joined together as one mesh. I'm not familiar enough with TinkerCAD to know why it would have a problem with them.
EDIT: Revised the model. Should be fine now, but let me know.