Q I've given up trying to nut this one out for myself, so I've come to you for salvation. In Navigator 4.04 or IE 4.01 I have come across the same Java error. It simply says that it cannot find the file java40.jar, that it's not in the "classpath". Then it lists what I take to be the whole classpath. I've read it through and checked my hard drive and it's where it should be. The error tells me to check the release notes and then install it properly, but there is nothing about this in the notes, funnily enough. Any ideas? Thank you.

A Files with the .jar extension are Java archive files that are used by Java applets. JAR is a platform-independent file format based on the zip format, which allows multiple files to be combined into a single file. A .jar file usually contains class files (which are the basic building blocks of a Java program), images, sounds and any other auxiliary files that a Java applet requires.

Java40.jar is a Netscape system file. It is basically an implementation of a large proportion of Sun Microsystems' Java Development Kit (JDK) 1.1, which contains the tools and software that developers need to compile, debug and run programs and applets that were written using the Java programming language. In order to run Java applets that are embedded in a Web page, Netscape Communicator 4.x needs to be able to load Java class files from the java40.jar file. The error you have mentioned may be due to Communicator being unable to load the file even though it exists and is in the right directory. ItÆs more than likely that the java40.jar file has been corrupted in some way.

As java40.jar is a Netscape file, itÆs odd that Internet Explorer displays the same Java error, but stranger things have happened before. The only fixes I have heard of apply to Netscape browsers, but with a bit of luck, they may also stop the error occurring with Internet Explorer. Here are three fixes to try.

1. If you have any security certificates, open up Netscape Communicator and export them before doing anything else. To do this, click the Security button, followed by the Yours link, highlight the certificate and click the Export button. Next, close Netscape, and start up Windows Explorer. Navigate to the C:\Program Files\Netscape\Users\username directory, and find the files called cert7.db and key3.db. Rename them to something else, such as cert7.old and key3.old. Fire up Netscape again and check if the Java error still occurs. If it does, try the next fix.

2. Set up a new user profile by selecting StartûProgramsûNetscape CommunicatorûUtilitiesûUser Profile Manager. Click the New button and follow the instructions. When youÆve finished, run Communicator again to see if the Java error recurs. If it still appears, move on to the next fix.

3. Completely uninstall Communicator by selecting StartûSettingsûControl PanelûAdd/Remove Programs. Click on the Install/Uninstall tab, choose Netscape Communicator from the list, and click the Add/Remove button. Follow any instructions that appear. Once Communicator is uninstalled, reinstall it to the same location as before, and your Java error should be history.