Comment form does not appear when switching from core Comment to Nodecomment

I have a site that is currently using the core Comment module for comments on a custom content type and the Forum Topic (core) content type. I want to switch to using Nodecomment module.

I installed Nodecomment and configured the aforementioned content types to use the Comment content type that Nodecomment installed. I have configured the global settings for Nodecomment to show the submission form below posts and comments. But when I view a node, the form does not show up. I see a link "Add new Comment" under my node which is supposed to go to the "node-form" anchor, but that is all.

I am wondering if I am in troublesome water because I have been using the core Comment module already.

I am also wondering if the comments that were submitted via the core Comment module should be showing up or if there is no compatibility. If there is no compatibility, then I am wondering if there is a migration path.

I should note that the module works as expecting on a fresh install of Drupal 6.

Thanks!