Joeminer, I have exactly the same problem. The plugin was working perfectly before. Since then I have done a couple of upgrades to wordpress, having currently version 3.3.2, but I really dont know when it started having problems sending the gift certificate email. I noticed because a cliente who bought a certificate let me know it never arrived. I think its very likely a wordpress upgrade broke it.
If anyone knows what could it be, let us know. Thanks!