SharePoint Document Library 404 Error

Help-

Any idea what would cause sharepoint's doc library's tree view navigation to break?

What-

We have a sharepoint site that uses the template Document Center to hold all of our docs. In the master page of the site there is a site hierarchy showing a tree view for all the folders in the document library. When clicking on the folders from the tree view we get a 404 error but navigating to the folder from the document viewer webpart on the child page works fine.

When-

The issue started yesterday when my boss was playing around w/ the appearance of the document library web part's Chrome type trying to add a link to the top to get better breadcrumb navigation when using the folder links in the webpart.

Example:

1. Clicking on the root folder of the document library named "Documents" goes to this url w/ a 404 Error:

   http://portal.domain.net/firmdocs/Documents

2. Go here we get a listing of the items:

   http://portal.domain.net/firmdocs/Documents/Forms/AllItems.aspx

What did I try

1. We didn't change the name of the doc library recently
2. I am going to do an IIS reset tonight
3. Tried changing the chrome type back to what it was w/ no luck.
4. Checked the master page and child page back up versions from a few months ago and no luck. Also the current fiels have not been edited anytime soon.