The Government Accountability Office (GAO) has found that the Interior Department missed out on $21 million in natural gas drilling fees due to accounting errors in its royalty-in-kind program, according to this article in the Denver Post.
A copy of the GAO's report can be found here.
[Update: The NYT is reporting that the Interior Department has decided to end the royalty-in-kind program. Interestingly, this program has been a large source of revenue for the government (about $6.6 billion in energy resource deliveries in 2008).
Also, the GAO recently released a report concluding that energy companies may have underpaid royalties by more than $100 million in 2006 and 2007. (Moved up).]