I have removed the default font at some time in past. When I tried to create a Print Format from an existing table the process failed without an error message.
After examining the code I found that the same should happen when no default print color and/or print paper is set.
Also the MPrintFormat.createFromGridView and createFromReportView functions seem to have the same issue.
I'd propose to run a check and produce a meaningful error message before the creation is attempted.
I hope to find the time to create a fix soon.