If you are talking about adding comments in ERwin when you add the audit column(s) to a table (or to update comments where the columns already exist), there are a few options:

Copy the column(s) from one table to another (ERwin 7.x). Highlight the column in the table you want to copy from, holding the 'CTRL' key down while dragging it to the new table. The comment will copy with all of the other column info.

Check out this article from InfoAdvisors on how to mass import definitions into ERwin:

http://www.infoadvisors.com/ArticlesVideos/MassImportofDefinitionsinERwin/tabid/159/Default.aspx

You can also use the ERwin API to import definitions. Use your CA site ID to log in and search the knowledge base for the API Reference Guide and presentations on how to use the API.