Redmine

I want to update a atribute inside the table issues

I write this code (to udate only the with the id 121)

issue = Issue.find(121)
     issue.update_attribute(:status_id, 6)

And Redmine returns stack level to deep

I have also tested

issue = Issue.find(:last, :conditions => { :id => 121 } )
issue.update_attribute(:status_id, 6)

and has been the same,

Could you help me ?

Thanks in advance