On one computer, I am using 2 ASIC erupter blocks at 666 Ghash, plus the cpu, at 1 Ghash, plus the video card at 30 Ghash. On another computer, I am using 1 ASIC erupter block, 333 Ghash, and on a third computer, I am using the video card at 10 Ghash. All miners were working before this, and after.
Also, on the main forum page, I saw several other people having the same problem on the same block.
Are you sure that you have not mistaken GHash for MHash?
I don't know of any CPU that can do 1 GH, or any GPU that can do 30 GH. Also I believe the Erupters do 333 MHash. If that is the case then you have less than 1 GH running. I know with my 180 GH I"m mining about 0.1 BTC a day. If you are mining 1 GH then you are likely not mining with enough hash power to have had found anything in the block you highlighted.