By error, do you mean the page ceases to respond or that you make an error?
If you mean that you mis-nurtured, it's simply a habit that develops. By your...ah, 50th day of playing, you'll be nurturing a hundred in a row before you slip up! If the page actually ceases to respond, try clearing your cache, refreshing/resetting, or using a different browser.
Remember, all:
Egglings
Warm > Cool
Cool > Warm
Dirty > Clean
Restless > Turn

Hatchlings:
Bored > Play
Derpy > Read
Weak > Work Out
Restless > Play

No, its not that. Its just that it says something like "Something went wrong, please refresh the page"

Ah. Have you tried clearing your cache and restarting your browser and computer?
Could you tell us your browser and operating system?

Operating system? I don't know what that is. But my browser is Safari

It seems like it may be a browser issue, though I recommend you ask Krin.
Have you tried the nurturing with a different browser?

No, but I have chrome, so I could try that
This also happens with the wardrobe

Ah...in that case, I definitely recommend Chrome. If you clear your cache and restart every once in a while, it runs much more smoothly. I haven't encountered any issues on Chrome that couldn't be fixed by a refresh.

Whats a cache?

*I apologize to any and all developers and coders, I'm going to mangle this explanation*

A cache is data stored on your browser for sites you visit. It might be images, or snippets of code, but they're used to make pages load faster, among other things, since the data is already there. When features like the Nurturing Grounds are added or updated, they might use new coding/data to work in different ways (even though it doesn't seem too different from the old nurturing grounds, Krin has stated that the coding is more efficient), and the stored coding might override that or cause conflicts and errors.
In Chrome, it's possible to clear your cache.

Thanks! I'm on Chrome right now