Cannot edit DC metadata of a project

I have checked out DC in writable mode. ie from inactive DCs

but in the project, i am not able to edit the DC metadata part.

and i am able to edit the web dynpro component part

this problem started after i re imported a model which was already added in the Used DC in my project

the changes of the model after re import are also not seen in the web dynpro component ( as i am using this model in used models in my web dynpro component)

i thought that after re importing the model i should go to used DC of the project where i have included this model project and add it again for the changes to be reflected, but i am not able to do so as i am not able to edit the DC metadata of the project.

i checked in, removed from client and re imported the project.

but still no help

the message when i try to edit the DC metadata is -

"The DC definition could not be checked out : The file .dcdef is checked out by others.!"

kindly help. thanks.