Here is a ZIP with the last version of Flash Player that is compatible with Windows 98\98SE\ME. (9.0.289.0) (Both IE and Firefox/Opera versions inside)
And, here's a link to the last version of Java that works as well if you need it.
You may have to right-click and "Save As" to download this one. Ignore the "Unsupported Operating System" message and it will work fine.
Requires Windows Installer to be already installed, get it here: