Another quote from the local Austin paper:
Originally Posted By: Austin American Statesman
Social studies textbooks, including the world history textbooks to which this resolution would apply, will probably not be adopted and bought until 2016. They were originally in the queue for 2012, but the state’s budget crunch has pushed back the purchase of new science textbooks as well as the social studies books.

The resolution is not binding and reflects the opinion of the board members - opinions that could change over time and with turnover.

The state has been having some funding problems for schools, and the political theater there isn't helping. We went from Rick Perry rejecting Federal Race to the Top money to now Rick Perry being listed as one of the petitioners on a lawsuit (pdf link) to secure Federal education aid. (More info on the story here). The main issue here seems to be due to an amendment added to ensure Texas actually uses the federal money on schools. In the past federal education stimulus money ended up being spent elsewhere.