Comments form not appearing in individual posts

Hi Guys

I have just downloaded WP 3.0.1 through Fantastico. Actually, I first downloaded the previous version (I don’t remember which) after which WP asked me to upgrade it to 3.0.1 which I did. Every thing is working fine except whenever I publish my individual posts after saving them in my customised permalinks, the comments form just does not appear below it. It can be seen in Preview but on publishing, it just cannot be seen. I did some amount of research and found out that if I use the default permalink, the comments form appears. It did. But I want to use a customized permalink, but unfortunately, if i do, then the Comments form fails. Please help. I am not a techie guy, just as a warning, and this is my first time with WP.