Does the user under which Transmission is running have proper access right to that folder?
What does it say currently for "download-dir" in your settings.json file? The settings.json file should be somewhere in /usr/local/etc/transmission/ if you haven't changed your config dir.
		
		
	 
"alt-speed-down": 50,
    "alt-speed-enabled": false,
    "alt-speed-time-begin": 540,
    "alt-speed-time-day": 127,
    "alt-speed-time-enabled": false,
    "alt-speed-time-end": 1020,
    "alt-speed-up": 50,
    "bind-address-ipv4": "0.0.0.0",
    "bind-address-ipv6": "::",
    "blocklist-enabled": false,
    "blocklist-url": "
http://www.example.com/blocklist",
    "cache-size-mb": 4,
    "dht-enabled": true,
    "download-dir": "/mnt/krigsvolds/Media/Downloads",
    "download-queue-enabled": true,
    "download-queue-size": 5
     "encryption": 1,
    "idle-seeding-limit": 30,
    "idle-seeding-limit-enabled": false,
    "incomplete-dir": "//Downloads",
    "incomplete-dir-enabled": false,
    "lpd-enabled": false,
    "message-level": 2,
    "peer-congestion-algorithm": "",
    "peer-id-ttl-hours": 6,
    "peer-limit-global": 200,
    "peer-limit-per-torrent": 50,
    "peer-port": 51413,
    "peer-port-random-high": 65535,
    "peer-port-random-low": 49152,
    "peer-port-random-on-start": false,
    "peer-socket-tos": "default",
    "pex-enabled": true,
    "pidfile": "/var/run/transmission/daemon.pid",
    "port-forwarding-enabled": true,
    "preallocation": 1,
    "prefetch-enabled": true,
    "queue-stalled-enabled": true,
    "queue-stalled-minutes": 30,
    "ratio-limit": 0,
    "ratio-limit-enabled": true,
    "rename-partial-files": true,
    "rpc-authentication-required": false,
    "rpc-bind-address": "0.0.0.0",
    "rpc-enabled": true,
    "rpc-host-whitelist": "",
    "rpc-host-whitelist-enabled": true,
    "rpc-password": "{e8e8e9317a398ba42ed3f253f5079768363a57c7H1ZA4PYu",
    "rpc-port": 9091,
    "rpc-url": "/transmission/",