The Wikipedia article on Ricci provides a nice summary of the facts of the case.
Ricci v. DeStefano is a 2009 decision by the Supreme Court of the United States arising from a lawsuit brought against the city of New Haven, Connecticut by eighteen city firefighters alleging that the city discriminated against them with regard to promotions. The firefighters, seventeen of whom are European-American and one of whom is Hispanic, had all passed the test for promotions to management. City of New Haven officials invalidated the test results because none of the African-American firefighters had passed the exam, stating that they feared a lawsuit over the test’s disparate impact on a protected minority. The complainants claimed they were denied the promotions because of their race—a form of racial discrimination. 
The firefighters appealed to the Second Circuit Court of Appeals, The court affirmed, in a per curium opinion, the ruling of the district court. A per curium opinion is one issued by the court as a whole, rather then an opinion authored by a particular judge..
To me at least this criticism is unfair for several reasons.
1) The case was a close call legally, in that it required a balancing of the "disparate treatment" of racial groups and the "disparate impact" on them. In this case the plaintiffs argued that they were discriminated against because they were not promoted due to their race, and the city argued that they if they certified the results of the test they would be subject to a lawsuit from the African - American and Hispanic firefighters, given that so few on them passed. There would be a disparate impact on them consistent with previous case law, therefore the city was likely to be sued.
2) The Supreme Court changed the standard of review here to a"strong basis in evidence" standard that was not in effect at the time the case went before the appeals court that Sotomayor was on.
3) There was substantial disagreement in this case among the members of the Supreme Court, not only over what the standard of review should be, but also to the facts (were there other tests the city should have given that had less of a disparate impact, etc.) Justice Ginsberg in her dissent, argues that even given the new stricter standard of review, the city's decision to cancel the test results was valid.
4) The one area where criticism of Sotomayor might be justified is that the appeals court ruling was extremely short, and provided little detail as to her reasoning and that of others on the court, for affirming the district court ruling.
5) Although the Second Circuit's decision in Ricci was reversed by the Supreme Court, it did so in a 5-4 ruling, further indicating how much of a legal split there is on this issue.
Here are some links.
The headnote issued by the Supreme Court in Ricci:
The Second Circuit Court of Appeals decision:
Two interesting articles:
A couple posts coming up in areas outside of law.