I have followed this tutorial on using NextGen plugin.
In my Dashboard, I create a new page. The WYSIWYG editor now has a ‘NextGen Gallery’ button. From this I select my album to add. The code added is… [slideshow id=1]
I would go to the html view, and change [slideshow id=1] to album to check to make sure that the plug in is working correctly. If it is, I would double check to make sure that you are using the correct ID.