Have you tried watching on that laptop from the same network as the Slingbox (over the LAN instead of remote viewing) ? If so, do you have the same results ?
I think your sustained transfer rate is the problem. The picture you included looks like normal artifacts caused by low-bandwidth streaming to me. You mentioned better quality on a different computer though, so there could be more to this. That's why I asked above how things look when viewing over the LAN- bandwidth shouldn't be a problem under those conditions. Hopefully the comparison will help you isolate the problem so you'll know for sure if it's got something to do with how your laptop is rendering video.
Regardless, you might have some luck playing around with the manual streaming parameters. The automatic settings are quite good, but there's no harm in tweaking the settings to better suit your conditions and personal preferences. Have a look here:
Hope this helps,
Thanks ArizonaSackbut and Denis247 for such quick replies and suggestions.
I have tried the Web Player and I still get the same funny lines. I have also connected via the LAN (with 1,500Kbps buffering) and it still has the same lines, so I am convinced it is my laptop. The stupid thing is that it is a highish spec new laptop. It has no problems running DVD's, downloaded files and stuff like that. The other laptop works fine ableit a little blurry, but no lines at the same buffering rates. Ahhhhh?
Thanks again for your help.