Never used Aspose myself but you should first ensure that your conversion from the PVK to the PFX format worked like you expected.
I agree with Poupou that full stack trace would help to understand where exactly the exception is generating and why. Moreover, if this problem persists at your end then you may also contact our support team via Aspose. Words forum as well.
We'll have to investigate this issue in detail and see if it is actually caused by Aspose.Words. And if so, we'll provide you the fix for that.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.