Nintendo has already offered an official solution. UPDATE: NOA offers save data repair service, announces plans for online save patching solution.
UPDATE: Nintendo has updated their official website with details on how to repair a save file suffering from this serious glitch. NOA is offering two methods of repairing player's Skyward Sword save data. Currently, you may contact NOA at 1-800-255-3700 and arrange for them to receive and repair your save data. Nintendo is also planning to release a program "that will repair save data for those who have their Wii connected to the Internet." Presumably this program would be published via the Wii Shop Channel or a similar mechanism. (Special thanks to Bryan Szollosi for the news tip!)
ORIGINAL STORY: A game-breaking glitch has been discovered in The Legend of Zelda: Skyward Sword, to which Nintendo has offered an official solution.
The glitch can be encountered when players complete the Thunder Dragon first when obtaining the Song of the Hero. After completing some unspecified tasks, the game would prevent you from completing the Water and Fire Dragon quests, forcing players to restart the game or select a prior save point.
Players have contacted Nintendo regarding the glitch. The company's response details what causes it, as well as how to prevent it from happening. The full response is as follows:
"We have been made aware of the issue that results in being unable to progress in the Song of the Hero quest. If the game has been saved after completing the sequence of events, it will no longer be possible to proceed through the game on that save file. The only options at that point are to either start the game over or to use an earlier save file to continue.
The situation is caused by performing the following sequence of events during the Song of the Hero quest:
1. At the beginning of the quest, go to Lanayru Desert to retrieve the song of the Thunder Dragon.
2. In the Lanayru Mine, speak with Golo the Goron.
3. Complete the Thunder Dragon's event, and receive his song.
4. Before heading to the forest or volcano regions, speak with Golo in the mine again.
5. At this point, the forest and volcano events will no longer occur, making it impossible to continue.
• This issue WILL NOT OCCUR if the Fire and Water Dragon songs have already been collected before collecting the Thunder Dragon's song. Talking to Golo in the Lanayru Caves will also NOT trigger this issue.
• If the game has been saved after completing the sequence of events, it will no longer be possible to proceed through the game on that save file. The only options at that point are to either start the game over or to use an earlier save file to continue.
I wish I had a better answer, but I'm afraid there currently is no other fix available. I can assure, however, that we are documenting all feedback we receive on this issue. Thank you for your patience and support."
It is expected that further releases of Skyward Sword will revise the game so as to avoid this glitch.