When decrypting something - the whole point is incorrect passwords won't give you an error, because that would defeat the point of having encryption (brute force until machine goes ding!).
All AES will do is 'decrypt' the information based on the set of rules it has using the information (key and initialisation vector, AKA salt), which can include decrypting to absolute garbage if the password is wrong.
AES should only throw an error if the password, and salt, are not (seperately) either 16, 24 or 32 bytes (as AES divides messages into 16, 24 or 32 byte blocks). Some variations of AES (EG ECB) won't even accept a salt.
Some encryption programs might include a wrapper front-end (lowers security, warning!) to know when it has successfully decrypted a message by putting inside a container that is essentially an overglorified message basically saying 'this has been successfully decrypted'.
Summary: assuming you supply the right password length AND the right salt (if applicable) AND the right algorithm (there's a copyrighted/commercial variant, note) it will always decrypt 'successfully': whether or not it decrypts into the message you want is another thing entirely.