Entity Framework new transaction is not allowed because there are other threads running in the session, multi thread save

I'm tryng to save on a DB the log of a multi thread processo but I'm getting the following error: new transaction is not allowed because there are other threads running in the session.

in each tread I have this function:

 internal bool WriteTrace(IResult result, string message, byte type)
    {
        SPC_SENDING_TRACE trace = new SPC_SENDING_TRACE(
                        message,
                        Parent.currentLine.CD_LINE,
                        type,
                        Parent.currentUser.FULLNAME,
                        Parent.guid);
        Context.SPC_SENDING_TRACE.AddObject(trace);
        if (Context.SaveChanges(result) == false)
            return false;
        return true;

    }

the Context is different for each thread, but the connection with the DB is always the same.

is there a way to solve this problem?

thank you Andrea