Dust?

Please have a look at the marks circled on the photos at

http://www.aaka92.ukgateway.net/Dust/

Is this dust on the CCD?

I have tried using a puffer to clean it. What else can I do ... are the marks more serious?

I should have added that I'm using an *ist D!

I suspect so, it's similar to what I came across (although I didn't have that many speckles). However, after blowing the sensor carefully they were gone. (And were later on replaced by new ones...).
Sometimes they show up even darker, sometimes they are hard to see...

Cheers,
Prieni