sumif

SUMIF bug in excel 2010

I've just upgraded to Excel 2010 (it was free as I bought 2009 recently). I now don't have another version of excel to test it on but I think I've discoved a SUMIF bug. Now I know the chances of me discovering a bug in excel are almost zero, so can someone tell me what I'm doing wrong, or alternatively tell me what their version of Excel...