This is a non-verified but plausible error report. If you create a new component that presumable has required fields, but do so selecting the non-default language of a multi-language tree, you can create a situation that causes a freemarker error. The "required fields" is a pure assumption on my part, as I hope that the reason such an error is introduced is that the template script assumes that required fields are actually filled out. It is however entirely possible that it has nothing to do with that.

Again, untested, I assume to reproduce, have a site with say English as the default (fallback) language and German as a second language. Go to a page, select German from the language selector, create a new component and save. The error will probably show up if you now select the default language in the language dropdown (English).

Please verify and rectify if reproducible.