I've seen this behavior a number of times.
You run a Selenium IDE script where you have a
type - token - text
scenario and Selenium will complain that the field "token" does not exist.
But it does - at this point, you are staring at it in the browser.
What sometimes seems to happen is that the page loads, Selenium sees the title and moves to the next line of the script but the actual fields haven't loaded yet and so can't be found.
The way around this is to look for a bit of text near the input field and then do a
That way the input field is there when the script requires it.