This has bitten me twice now so I figured I should write about it to help me remember. It involves the error “ERROR 010240: Could not save raster dataset to”. I got this error everytime I tried to save a GRID from the NLCD 2006 img file. I found the following link that explained a lot.

http://support.esri.com/en/knowledgebase/techarticles/detail/38972

I'm still struggling with this so I may edit this post later if/when I discover more about it but the link will let you know that its not just you.