These two errors are generic connectivity errors and could have many causes such as loss of connectivity to the internet, internet connection timing out due to high network traffic, internet connection interrupted due to a laptop entering sleep/hibernate mode etc...
Basic troubleshooting steps would include:
If the problem persists then it would indicate a high network load for the Nokia Music service. This can be solved by simply trying to download the desired track at a later time.
Contact Nokia Care if this problem isn't resolved by any of the processes detailed above.