How can I complete my HP Photosmart d110 wireless connection?

My HP Photosmart d110 printer came in a package with my Macbook Pro. It worked well before I decided to make our wireless network secure. I have a Dlink router. I can access the Internet from my Macbook Pro, and my wife can access the Internet from her HP laptop. I can no longer get my HP Photosmart d110 to access my router, even when I tap in the network password.
I did change the setup of the router from WEP to WAP (whatever that means) when I secured the network. Is it possible that the printer can’t deal with WAP?