If you come across following error don’t be panic.
warning: can not save changes to the repository because,
[nQSError: 61013] File error: path= C:\OracleBI\server\Repository\paint.rpd , code=31: There has been a sharing violation.
May be its because of, you have started working on repository (offline mode) then started BI Server, after server services start, if you try to save repository you will see above message.
If you want to save all your changes just stop BI Services, and then save repository it will save all changes made to repository.