I'd really like to help you, but I can't by lack of information and telepathy skills
Please be more precise than "The Ajax statement does not work".
1- What exact "Ajax statement" ?
2- What exactly "does not work" ?
3- What exactly do you want to achieve ?
4- What is exactly your configuration (configuration screen-dumps are welcome) ?
Please understand that to help you we need to understand:
a- what you want to do, and
b- how you tried to do it, so that
c- we can if needed reproduce your setting on our development test installation.
Please help us help you
www.joomlapolis.com/help-us-help-you