The no shipping methods available error means that either there is no valid shipping methods for the selected country, weight, order total, zip code or location. If real time shipping is enabled this could also mean that there is an invalid address for either the destination or origination or if no real time rates have ever been returned the setup is not correct. Make sure that valid shipping methods are created for every possible combination available.
Examples of missing shipping methods:
Shipping by weight, only defining a weight range of 5-8 pounds. Any order above or below that weight would have no valid shipping methods.
Flat fee shipping, only defining a shipping for the United States. Shoppers outside the United States would have no valid shipping methods.
Create as many shipping methods, tiers, costs etc as needed to cover all needed combinations or use one generic shipping method for all cases.