Sidebars Disappear On Entry Page

I have a three colomn Tulip theme and both of my sidebars show up on all my pages except for my main entry page!

I’ve made several modifications to the original theme and added a few plugins (a couple of which required a few hacks) but .. wouldn’t any problem be blog-wide and not just the entry page?

How can I fix this? This is my business site and I’m losing clients/ad links because of this issue. Grr.

Thanks in advance for your time and help!