I found this issue when I had extended and created my own theme for the admin area.
These buttons use FLASH.
So if your browser does not support flash - then they will not appear.
Ensure that the app/design/adminhtml/default/default/template/media folder exists and that there are 2 files within it.
Ensure that the skin/adminhtml/default/default/media folder exists and that there are 3 files within it.
If you have created your own theme (ie Theme: "mytheme" and Package "mypackage") then ensure the above applies for:
Let me know if you have any trouble.
If issue is solved, Click "Kudos" & "Accept as Solution"