NextGen Gallery not allowing me to display the_excerpt();?

I do not know how the plugin prevents you from using the_excerpt().

I guess the reason why the plugin does not want you to use the_excerpt() is as follows: the_excerpt creates an excerpt from an article by cutting it after the first 50 words. This might cut in the middle of a <script>...<script> fragment, which NextGEN had inserted in order to display a gallery as slideshow.