From what I heard, Gubler's wife is a mega-premie, and from what I understand, Gubler was blackmailed by Rawat's goon-lawyers and told that they would tell his wife about the leaked document, if he didn't sign the affidavit.  I thought Gubler felt his marriage might be over if she found out. 

It's kind of hard to believe that he believed she wouldn't find out anyway, however, and, of course, it doesn't excuse the lack of backbone in lying under oath to protect himself from the rath of his wife.  Who knows, through, maybe she is an expert in the martial arts or has a large gun collection.  Who knows?  

Fear can get people to do a lot of dumb things.