Make sure Java is enabled in your browser.

For Netscape browsers, select Preferences from the Edit menu, then select Advanced to see if there is a check mark next to "Enable Java".

For Internet Explorer browsers, select Internet Options from the Tools menu, then select the Advanced tab and scroll to make sure that the "JIT compiler for virtual machine enabled" option is selected. If no Microsoft VM section is present, you will need to either install a newer browser or download the Java virtual machine from Microsoft. To add the Java virtual machine to IE 5.x, follow these steps:

Run the installer for IE 5.
When the installer launches, you will see 2 choices:

• Install Now -- Typical set of Components
•Install Minimal, or customize your browser.

Select the second one "Install Minimal, or customize your browser". In the options box above the itemized choices of components to install, select the "Typical" install Add the Microsoft VM by additionally clicking the check box to the left of "Microsoft Virtual Machine".
Complete the rest of the installation normally.