If you are using Ubuntu, Kubuntu, or Xubuntu, then just use your Adept Installer (KDE) or Add/Remove (GNOME/XFCE) package manager to download and install it. You can also try the Synaptic Package Manager to download and install packages. For Adobe Flash Player, you don't need to download it directly from Adobe. You can also use the Plugin Finder Service to download Adobe Flash when you go to a website that requires flash. An example of a website that requires flash that will notify you of it and download and install it. You should have Ubuntu, Kubuntu, or Xubuntu 7.10 or later to do this. You need to check your internet connection, as well. If you can get onto the internet, then you should have no problem using the services above to download and install Flash. You can download the Debian (.deb) file for Firefox from Adobe and use the Debian Package Installer. This should work with OpenSUSE as well.
However, if you don't have the Ubuntu kernel, and use Dreamlinux or other Linux distribution, then use the package manager with your distribution. Hope this helps. If none of these work, then your internet connection may be the problem or you need to upgrade to a newer version of the linux distribution.