Nice photos, Luis!
I browsed a bit through the EXIF-data and found something curious at DSC_00070007: You shot at 1/1600sec at f5.6 (certainly to have a shallow dof) but at ISO 400(!)
With ISO 100 you would have ended up with 1/400sec which is certainly enough to avoid shake/blur. Why did you crank up the ISO?
A previous attempt proved to be a little too dark for what I had in mind. As usual, my camera was on aperture priority mode, and as I wanted to stay with f/5.6, increasing the ISO was my only choice to get more light on the subject, as changing shutter speed myself would have involved turning to manual mode *shivers*.
Yes, I could have changed exposure compensation to maybe +0.3 or +0.7. But I simply didn't remember that feature at that time.
Oh, and as you know, the D40 starts at ISO 200.
Now, on both DSC_00290027 and DSC_00280001 you can see ISO 800, as for those two particular shots, there was a slight wind and the flowers were moving back and forward, so I knew I had to get the fastest shutter speed possible. Setting a high ISO allowed me to keep an f/5.6 aperture and have the camera calculate a fast shutter speed.