Many of my scribes are 8-10 minutes long, with lots of text and images. Since this typically causes the software to have render problems (or not render at all), my simple hack is to use a screen recording software and simply playback the scribe while recording the video/audio with the recording software. I use aTubeCatcher, which is free. Just wanted to pass this on in case it's helpful...
Here's a bit of information that may help you to keep the memory usage down. Also we have improved the rendering function in our latest patch release - VideoScribe 2.1.2.
A common reason for VideoScribe crashing is because you are reaching the memory limit that VideoScribe has available. You can check the amount of memory VideoScribeDesktop is using by checking Activity Monitor (Mac) or Task Manager (PC) when your scribe is loaded. If the memory usage is getting above 1.2GB then this is where crashes can start to happen (VideoScribe cannot use the full amount of a computer's RAM). If you are already near this limit and you try to add more elements then this will tip it over the edge of the memory limit.
I would suggest that you try to get the memory usage down using a number of methods including reducing the number of images and/or text, not using too many different fonts, optimizing images before you import them so they are the smallest size possible and reducing the amount of zoom. You could also split the scribe into smaller parts and edit them together after you render them. There are a number of free tools you can use to optimise your images which are outlined in a post on our blog entitled 9 Free tools to pimp VideoScribe.