Here is a web page that gives 3 different results for the missing-image.gif link status.
I get a green -- '40 - not found' status.
I get a green -- '200 - OK' status.
On my local C: drive I get a red -- 'File Not Found' status.
Can you have a look.
Here is some addition.
Checking from home I am getting a different result for the second entry.
I get a red -- '0 - Object moved (Redirected)' status. I have set redirected links to be set as an Error in the Tool options.
At home, I used 7.0 B3 and at the office it was 6.53.
It seems web server setup affects the results.