author is not able to translate a document

reproduction:
create an english news document, give it a title, save & close it, translate to dutch, translate the title in the dialoge, submit the dialogue

result:
"the action failed" message
----------------------------------------------------------------------
Reopening the issue.
1. Start gogreen CMS
2. login as author and translate a published document to French

Issue -
1. Though the document is translated exception is thrown as Action failed, error occurred. (refer author translation exception.txt)
2. Translated document session is not saved here there are three observations
a) As author, in the same browser I can see document is translated and its visible in French. Though I am not able to perform further actions like publish or edit etc
b) When I log in as admin in another browser and navigate to same place i.e French Go Green Folder (Hippo Mise au Vert) I see the same document in English (screen shot attached)
c) When authoer logs off the session following exception occurs (refer FR translation logout exception.txt)