Why is_home() is_single() and other is_ doesn’t work on My WordPress 2.7

I was fix the Problem

case closed ??

What did you do to fix this problem? I am experiencing is_home() and is_front_page() returning true for all pages in version 2.7

Jauhari,
If you post a query, its common/good practice to post up your solution as well and follow up. So you help yourself and help the community.