There are a lot of reasons why images, styles and scripts will refuse to work for you on a sharepoint site. I have come across some of them, and I want to share how to troubleshoot this.
One reason this may happen is that your Internet Explorer is blocking the scripts. I had a lot of people complaining about how they installed sharepoint on the server, then created a web site, then tried to create a list item or upload a document, and non of the buttons would work!
You will find that often this is accompanied by sharepoint constantly asking you for authentication each time you load a page, and sometimes more than once for each page before letting you see the page.
This was because they were working from the server, which by default has the "Internet Explorer Enhanced Security Configuration" installed.
If you must work from the server itself, either remove the "Internet Explorer Enhanced Security Configuration" (control panel->add remove programs->add/remove windows components) or add the site to the trusted sites list (not guaranteed to work. I suggest you remove the security block).
Another reason is a problem with the alternate path mapping in central admin. The Alternate Path Mapping are not configured so that the path you are trying to use is properly managed by sharepoint. For example, you may be using http://localhost while sharepoint is configured to accept http://portal.
I dont know why this happens, most of the time the alternate paths are configured correctly for you automtically. But I have seen a server (just today I had 2!) that lost it...
Open the SharePoint Central Administration Page, go to the Operations page, and click on "Alternate Access Mapping". Make sure that the url you are trying to use is in the list, and if not- add it!
These are the two instances of this problem that I have witnessed. Got more? comment!
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