Problem with cookies

Hello,
I have the following problem – I’ve developed a site and there is a simple login form which sets cookie. In Windows it works fine, both on Firefox and IE9. On my customer’s Mac it the cookie is not saved (checked with Safari and Firefox). On other Mac computer it works fine. The problematic computer runs Mac OS X version 10.6.6
I guess it’s something about privacy settings, although we’ve checked Firefox settings and they allow cookies.

Any idea what can I check/do?

Thank you in advance.

It has to be a preference setting. Safari, FF, and Chrome will all save cookies unless the privacy option or selective cookie save option is selected. Works basically the same way that the Windows browsers do. Your customer is doing something wrong.

Thank you for the answer.
It means that there is no OS setting that can prevent cookies?

No, it's strictly done from within the browser being used. There are no general security settings in "System Preferences" that deal with cookies.

Thank you, this information is very helpful for me.