Problem converting

[AlphaNova]

I'm trying to convert from the latest version of phpBB2 to smf 1.1.4, but I keep getting this error message:

INSERT INTO `b13_1126939_original`.smf_topics

Caused the error:

    Duplicate entry '3518' for key 1

So far I can't find a way to solve this.  Any help?

[KGIII]

Have you searched the forum for "duplicate entry" perhaps? I am NOT a converter guru. BUT I know there have been piles of topics on it.