Yes. This happens because one of your files with either common or server affinity has a direct (or secondary, tertiary...) DOM dependency. You can see from the stack trace that YUI fails to load the dom module, because there is no window. You should upgrade to mojito 0.3.28 (if not already) and look at the first few lines of the console output after mojito start. There it will show a warning, which explains which of your components is having a DOM dependency.