There are several problems with the statements of Marohasy. The claim of cooling since 1998 is only true if you're talking about the USA. Since the issue is GLOBAL warming, not US warming then you need to consider the whole globe.
Globally, 2005 was hotter than 1998, so over this period that she says there has been cooling, the global temperature has actually gone up. Oops!
The bigger problem is cherry picking particular years to make a case, when that doesn't say anything about trends. I found a penny on the ground one day, and the next day I found a dime. Does that mean I should expect my income to increase by 10 every day? In a week I should expect to get a million dollars a day? That's the kind of ridiculous result you get when you pick a couple of arbitrary points and call it a trend.
When you look at the 5 year moving average of global temperatures, it continues to go up. There is no evidence of cooling or even a plateau.
Data @ NASA GISS: GISS Surface Temperature Analysis: 2005 Summation
Her assertions are so completely wrong that it is not possible to attribute them to mistakes, they are intentional attempts at deception. In short, Marohasy is full of BS.