There could be a range of think going on. If google does not think your page is important then it may not be going deeper. Do you know what your page ranking is? can you post the url and I will have a look.
might be you must be violating the google webmaster rule ??? pm me ur site address let me check for u
???What looking at the someones site?. I don't want to register as an owner in google webmaster tools. I would need more then the url to do that. I planned on checking the source and the page rank to ensure there was nothing silly going on. Like javascript links or a flash navigation. All done with the best intent.
You could have kept the indexed page. In some cases, it requires some time to index the inner pages. Check the contents on your inner pages.