Hi Kathy

If am looking at it right now and it should work.

If you are using this version

http://www.zen-cart.com/downloads.php?do=file&id=60

I am the current maintainer of it.

My wife uses the same version (albeit the NZ part), and her store only sells virtual products, We commented out the piece of code you mentioned and virtual products work fine.

If your site is still testing, try adding a new product, not a virtual product, then go to check out with only that product in your basket and see if the option comes up?

I will do a quick test on my test site shortly

Please do report back how it goes or if you have solved the issue. Cheers