Upload image error on front page

Hi,

I’m already a week working on this one.. Searched the whole web but i cant figure it out.

I’m trying to make a front end posting form with the tinymce and media insert button. I called in the wp_editor in my formidable form, but when visitors want to upload a image i get the upload error. When i enter the upload form as administrator there is no problem and all works fine and healthy.

I disabled all plugins and it still didn’t work.

All registrated users have the author role btw.

Is there a solution or fix for this issue?

Greetz,

Jacco