Agreed - when things are working properly, going to the permalink for a page/post should bring up that page/post and not a "not found" page.
Two things to try:
1) Reset the permalinks, as Christine suggested above.
2) Disable the WP Sticky plugin and try to go to http://iheater.info/iheater/ - does this work?
Also, verify that the iheater post has the status Published. You can check this by viewing the post in the Dashboard and looking in the top-right widget on the post editor screen. If it isn't published, it wouldn't be available for viewing, which would cause the "not found" page to be displayed. I wouldn't think that the WP Sticky plugin would show it if it weren't published, but I don't have experience with that specific plugin either.