Could NASA be Cooking the Climate Change Books?

It certainly seems like they are trying to stonewall one skeptic who is going to sue them for the information.

Chris Horner, a senior fellow at the Competitive Enterprise Institute, said NASA has refused for two years to provide information under the Freedom of Information Act that would show how the agency has shaped its climate data and would explain why the agency has repeatedly had to correct its data going as far back as the 1930s.

He wants to know why NASA had to alter some temperature data:

The numbers matter. Under pressure in 2007, NASA recalculated its data and found that 1934, not 1998, was the hottest year in its records for the contiguous 48 states. NASA later changed that data again, and now 1998 and 2006 are tied for first, with 1934 slightly cooler.

Yeah, I would like to know if these numbers were altered twice due to errors or was it another case of "hide the decline?" If it was errors then there needs to be transparent checks in place to make sure it doesn't happen again.