Click on "Start" and select "Control Panel".
Find "Java" and double-click the icon.
Under the "General" tab choose "Settings".
Make sure that the checkbox at the top is CHECKED and choose "Delete Files".
Make sure both checkboxes are checked and choose "OK".
Now, close the other windows by choosing OK and try to enter/open your Collaborate/Elluminate session again.
Note: It will take a little while longer to download and start Collaborate/Elluminate after doing this.