Custom Tangible Product - Help Needed

Greetings,

I'm trying to follow the directions on this page (http://drupal.org/node/135862) to make quantity discounts on a tangible product in e-commerce.

I followed the instructions using the generic module (that is, find "generic" and replace with "customname") and added the code in the comment at the bottom of that page to the module and got everything up and running just fine. The module installed fine and everything behaved as it should.

However, I need to dovetail with the Shipping API and Shipcalc, so, I have to make a custom module based off of the tangible.module.

I did the same procedure of find and replace and made sure that instances of "tangible" were replaced with my "customname". (Note: I am not a programmer. I can kind of find my way around some PHP but am very ignorant as to how it works.)

Well, with that custom module in place and the customname.install file ready to go, I go to admin >> modules and enable the module and then get a white screen on the whole site. It's not till I delete the module from /sites/all/modules that the site comes back to life again.

I'm wondering if anyone could offer advice about what I'm doing wrong. I'd really like to get this up and running, but I'm at a loss of what to do now. Any help is greatly appreciated. Thanks!