Hi,
just downloaded the excerpt plugin and I think there is a little bug in it.
I was testing a couple of posts with the plugin and some only had one or two words in the content (some also had a single word and an image).
The plugin inserted the ..read more link after the word with the image and on the post with only a single word it only displayed the ..read more link and the word only appeared after I clicked on the link. On the post with two words in it (Test Post)it broke after the word Test and displayed the words Test Post after clicking on the ..read more link.
In the setup I set the word limit for the excerpt at 150, which seems to work fine with the longer posts.