How to fix "iTunes has not yet accessed in your computer, please activate iTunes first to relaunch the program" error

If this message appears when start the application: iTunes has not yet accessed in your computer, please activate iTunes first to relaunch the program, here's the solution to fix the problem: 

Check where you store your iTunes library. If you store your iTunes library to an external drive, the application might does not works well. 

Do the following:

1. Log in to your computer as Admin account.
2. Change the primary language of Mac OS to English if it's not English: Click the Apple icon in top menu, choose System Preferences > Language and Text, and drag "English" to the top of the list.
3. Open iTunes,  and in the top menu bar, go to  iTunes > Preferences > Advanced tab. In the resulting window you'll see the media library path. Make sure it's saved to /Users/Your Account Name/Music/iTunes/. if it's not, simply click the Reset button to restore to the default one.
4. Close iTunes, restart your computer, and open iTunes again.
5. Launch iPhone Ringtone Maker to try again.

If you have another Mac machine, also install iPhone Ringtone Maker for Mac there to see whether the same error appearing. This error might occur on some special Mac environment.