DOC to EPUB Prob: Duplicate ID Anchor

Hey everybody,

I have a book that I'm trying to get into iBooks via Smashwords. I converted it from .DOC to .EPUB with Calibre and SW's ePub Verification check found a single error:

"could not parse index_split_003.xhtml: duplicate id: anchor3"

I taught myself the nuts and bolts of XHTML and CSS at my own WP website, but have no clue what that line of text means. I suspect that in my TOC a duplicate is popping up, but am not sure.

Please help!