The message tells you that "Drive C is mounted as local directory c:\games".
I see how this can be misleading. You assigned c:\games to be drive C so the message sounds backward.

However, I don't see how you could expect to go up from the mounted directory. DOSBox is treating the actual c:\games as if it were C:\ within the emulated environment. There is no parent directory of the drive itself.

What were you trying to accomplish that you needed to mount the physical drive for? Maybe someone can advise you on that instead.