D7000 SD Card Problems...
I have the same 8GB memory cards for my D7000. I have not had any error messages but noticed that for 1 pair (one in each slot) it suddenly took about 30 seconds to write each photo that I shot in RAW. After I was able to download the photos and reformat the cards in-camera, the problem went away. I use 3 pairs of 8GB Sandisk cards in rotation and always use the in-camera format function for each newly inserted pair. I hope the Sandisk quality is not slipping. . .
|Thunderheads With Egret by Buzz Lightyear|
|Double Rainbow; Abiquiu, NM, USA. by abiquiuense|
from After the Rain
|White Tern-2289 by vbuhay|
from A Whiter Shade of Pale