Invalid argument when adding first preset

I get this warning error when adding a preset when none are created, and just after setting the path for FFmpeg:

Warning: Invalid argument supplied for foreach() in element_children() (line 6370 of ~/includes/common.inc).

It only appears when there are no presets. If one is previously configured it will not show up, but if all presets are deleted, the error will return the first time a user clicks "Add preset".