The cause of that error message is that the browser was unable to download the JVMDetector.class file from the server for execution.

This issue is more transparent with Netscape 4.x since it treats a missing applet as a warning and keeps executing desite the warning. Whereas Netscape 6.x and higher, as well as Firefox, treat the missing applet as an error and the page stops executing. This typically results in the error only being noticed with NN 6+ and Firefox.

The install instructions provide guidance on where to place this class file. The file is JVMDetector.class and it should be placed under your server's document root.

The browser will normally request the file from the same directory as has the applet tag, so when running ASP or JSP pages you can put the .class file in the directory holding the ASP/JSP file that calls these BrowserHawk tests.

Note: This applet is only required if you are using BrowserHawk to detect JavaVendor, JavaVersion, MSJVMBuild, Plugin_JavaVer, OSName, OSArch, and/or OSDetails. If you are not interested in any of these properties, make sure you are not calling BrowserHawk's extended property method and passing in "ALL". This is because when "all" is used, BH will include these Java tests which are not necessary since you are no interested in these properties. Instead, change "ALL" to the list of only those properties in particular you want to detect, and then there is no need for the jvmdetector.class file.

Note to BrowserHawk4J users: For a servlet accessed as /servlet/Foo that's not possible (because /servlet is a virtual directory and can't serve files) so in that case you can set the JVMCodeBase property on BrowserHawk to the directory containing the file, such as "/" if the file is placed in the document root's base directory.