Java is not installed
If you came here by clicking on the Big Green Arrow, then your web browser does not seem to have support for running Java applications via Java Web Start, perhaps because it does not have a recent version of Java installed.
Perhaps this is a false alarm, and Java Web Start is working in your browser, although we have not been able to detect it. As a first step, you should try to launch GeomLab directly by clicking on this link:
You will probably need to accept a security certificate before the program will start, and the Java installation on your computer may automatically upgrade itself first.
If your browser doesn't seem to know what to do with the link, then that's probably because Java is not in fact installed at all. In that case, you can download the free Java plug-in from Oracle by clicking here and following the instructions. When the Java plug-in is installed, return to the home page and try again.
On some browsers, it is also necessary to create a manual association
between Java Web Start scripts and the javaws application. The mime
type for this is application/x-java-jnlp-file and the extension is jnlp.
As an alternative to using Java Web Start, you can download the GeomLab application as a JAR file and run it, either by double-clicking on the file, or from the command line, using a command like
java -jar geomlab.jar
This will avoid any problems with signatures and certificates.