When you buy a token with IRL money, you can only use it to sell on the AH for in-game gold.
If you wish to purchase game time, you buy it either as a subscription or in a two-month time block when using IRL money. The only way you can use a token for game time is if you purchase one from the AH with in-game gold (or to add to your Blizzard balance for other services).
I don’t know why it would say cannot auction, as that’s all you can use your token for when purchased through the in-game shop.
But here is a handy dandy chart one of our MVPs put together. Definitely click on it to go to the proper post for formatting.