Very rarely, a computer will be set up so the Collaborate launch file (.JNLP file) opens with something other than Java. To further complicate matters, there are different components of Java, and the .JNLP file can only be opened with one of them.
If this happens to you, there's a one-time process that you have to go through to insure that your Collaborate .JNLP sessions open properly every time you launch them.
1.Go to Collaborate and attempt to launch a session. Make sure that no matter what happens, you save the .JNLP file someplace you can easily find it (such as your desktop). Right-click the link and choose "Save As" if you have to.
2.Find the .JNLP file and right-click it. It could be called something like "get.session.launch.event"; more commonly it will be called "get.session.link.jnlp".
3.From the drop-down menu, choose "Open with". Then, on the secondary menu that appears, select "Choose default program..."
4.On the "Open with" dialog box, make sure that the "Always use the selected program to open this kind of file" check-box is checked.
5.Click on the Browse button.
6.At this point you can either search for the Java program or navigate to it. It's located in C:\Program Files\Java\jre6\bin (on Windows 7, it will likely be in C:\Program Files (x86)\Java\jre6\bin), and it's called "javaws.exe" ("ws" meaning "web start").
7.Once you find javaws.exe, select its icon, which will return you to the "Open with" dialog box. Click OK.
Now all .JNLP files on your computer will be properly associated with the "Java(TM) Web start launcher", and will open as intended when you click on the Collaborate session links in Blackboard Learn.