According to the Worlds page on Memory Alpha
Memory Alpha wrote:
As of late 2008, Decipher has let lapse their license to produce/sell RPG material based on Star Trek. Thus, this supplement is no longer available through the sole online vendor, Drive-Thru RPG.
Sorry. I guess that's a major drawback to eBook-only releases... you can still find old copies of the hardcopy Decipher books in hobby stores or on ebay, but I guess the softcopy-only ones are gone forever...