[TYPO3-project-realty] Formidable::Mayday on frontEndEditor and frontEndImageUpload

[Olli]

Hi Guys,

i am having difficulties getting the frontend editing and frontend 
imageuplaod to work. everything works just fine, but as soon as i click 
on either "fe-edit" or "fe-image-upload" i get the "Formidable::Mayday" 
error page.
i am not using two plugins on the same page. all PIDs are managed in the 
setup - not in the flexform of the page (although i tried that too).

TYPO3 4.3.8
realty 0.4.0
ameos_formidable 1.1.0

any suggestions what might cause this problem?

greetz,
oliver