project management- can't save when adding people to 'Team' rel tab in a project


i started working on project management some time ago and i could set project team members in the "team" rel table and save the project wtihout any problems. But now when i create a project from a template and set the team menbers and roles and try to save i get an error telling me that no item of type 'project team' was found. i dont get this eror when i don't specify team members. i also don't get any error when i put people in assignment tab of activities.

and i dont remember about modifying anything related to project team

also i just notice that when i try to complete an activity on the acw with an identity set in assignments i get : "Project instance is not found for this Activity. " its also new but i d'ont know if it's due to the same thing

i have no idea where this could come from so any pieces of advice would help me a lot, don't hesitate to ask me for additional info if needed