save custom term – hook create_term doesn’t work

I found my failure…
a few months ago I added the following line to my code:

if(!(defined('DOING_AJAX') && DOING_AJAX)) {
    include_once 'mytestfile.php';
}

in this file, I add my action for creating a term…
with this line, i wanted to prevent to load some files that I doesn’t need when I’m using AJAX…
but wordpress is using AJAX for create a new term..

now I removed this if-statement and everything works well…

sorry that I stolen your time for this stupid failure..
but maybe someone has the same problem and is happy about my post 😀