Photo Gallery error

I have a couple of photo galleries on a site that had been working fine. Now
though when I click on Configure to make changes, the configuration window
pops up and I can see the menu items, but the rest of the box is totally
grey. If I click on a tab (Images, Thumbnail, Photo), I receive an error
message:

An error has occured in the script on this page
Line 429
Char 4
Error 'this.getCurrentItem{}' is null or not an object
Code 0
URL file://C\Program Files\NetObjects\NetObjects Fusion 9.0\NetObjects
System\FSI\PhotoGallery\Properties.html

I hope there is a way to repair this?
Janice