Upload image on block and pages in backend CMS

Hi we have found an important bug on page and content block backend editing panel.
When you try to add an image from the text editor it redirect you to a 404 page not found.
you can see this images:
Attachment 32231Attachment 32232
This bug is present in the quickstart too.

Have you a solution?

I just installed a lastest jm lingerie package and did not see this issue, is your lastest ? I think you can try to upgrade your jmbasetheme extension, if doing that not help you can pm me your url, admin account, FTP info I will fix this for you