I found this on the BI forums regarding your error message.
http://feedback.arma3.com/view.php?id=20427It seems it's related to All in Arma in some fashion. Several questions regarding your error message.
1.) Have you had this message more than once?
2.) Is this message from simply starting Arma (when it initializes mods), or from loading into a server?
3.) Have you checked your RPT file to see if it supplies any further information?
4.) When you downloaded the AiATP, you choose the 6.5 gigabyte Terrain Pack, and not the Lite pack (2.something)? If you did not downloaded the six-and-a-half gig All in Arma, then you've got the wrong one.