Calling NAG e04ncf with ifail = 1 terminates app

I'm debugging an app in IVF that calls the NAG routine e04ncf. I have tried to use -1 and 1 for ifail but the app is still terminated by NAG.

I'm using the 32 bit intel compiler on Windows 7 32 bit and the NAG 20 library. I can run the Graph.exe example and this works Ok.