A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
Historically, PPT whining about not enough memory might have meant two things:
It ran out of memory, or
It ran out of other reasonable excuses and whining about memory was the last one on the list.
It seems unlikely in this case that lack of memory is the problem. On the other hand, there are other resources (file handles, stuff like that) that it might consider to be memory related.
What happens if you set the links not to update automatically, at least as a test? On a copy of your "real" presentation, of course.
What sort of objects are these galleries?
If possible, download the demo of my FixLinks add-in from http://www.pptools.com and run a FixLinks report, post the results here. It'll give you some idea how much space the links are taking up. PPT can get squirrely when the link space used exceeds the link space alotted.
(Echo Swinford: edited to activate link)