I just bought a book that won't convert to AZW3.

Now you know I'm tech challenged and the most I've done with Calibre is epubsplit. The error it gives me in Calibre is 274 pages long.

Is there an easy way to see what the problem is and fix it? I tried converting to epub [even though it already is an epub] and then to AZW3 but that didn't work either. I just want the easiest way to fix this, and obviously posting 274 pages of error isn't feasible...

Oh, and I did try using epub split but that didn't work either, it broke the book down to like 2-3 sentences per page. Gah! Easy fix anyone?