HP 7280 all-in-one scanner problem

I'm unable to scan from my wireless network and can't figure out why. I've added HP Solution software to my laptop, but receive the message No HP devices have been detected when I attempt to use. I have used the webscan feature on HP support from my laptop - an image appears in the preview window, but the image is not transferred to the laptop when I depress scan.

The all-in-one is connected to my desktop by USB; no problems there. The print function does work from my laptop, but not from HP Solution.

My desktop is on Vista and the laptop on XP.

Can someone offer a solution?