I would like to disable the "next" navigation button until a question has been answered. I understand this can be done through actions, however I am at a loss for the correct syntax. The button needs to be enabled once the answer has been submitted.

If anyone has done this successfully, would you be willing to share the syntax?
thanks,
Jesse

At slide level (left of your work area) select action and "afterdisplay"
example. Action is Display and show object, which is an image of your disabled button. On the working slide this should be located in the exact location of the "Next" button which is probably on your Master Slide. When your question opens only the disabled button image is shown. On the working slide select Display action on the disabled next button and choose, hide on "item selected"

If you want to disable the navigation buttons that are added from the template it is a little different to Davids description above and involves a few steps.
STEP 1. Click on the ion for the specific page. Right click and from the drop down options select actions. You then select from the event types 'afterdisplay' and then a navigation action. Chose the Next button from the navigation objects drop down and then select the action disable. The page now loads with the next button disabled.
STEP 2. Select the question object and right click selecting the actions option from the drop down. If you only want to have the user attempt the question select the Event as 'On Attempt' then add a navigation action. In the navigation action dialogue again select the next button option and the action as enable.
You should now have a page that loads with the next button disabled, indicated by a cross through it. Once you attempt the question object the cross will vanish and the next button will be enabled.
If you look at the options you can there are a few more actions available related to the users response such as On success, On Failure etc that could be used in different ways.
For example add an on Failure event followed by a Call event to push the user back to a specific page containing more information, or use a Display action to display a hidden pop up on the same page containing more information relevant to the quaestion.
The possibilities are almost endless!!