YabbSe 1.5.5 to SMF : duplicated entries

[Marcosms]

I'm planning to convert my yabbse forum to smf.
SMF installation was easy but I had no success converting the yabbse forum.
I keep receiving error messages for duplicated entries when importing messages.
This is the kinda message I receive when running the converter:

Converting posts (this may take some time)... Unsuccessful!
This query:

    INSERT INTO `medfly_smforum`.smf_messages
........(here is a long string of messages before the end message)....................

Caused the error:

    Duplicate entry '16986' for key 1

If I try to convert again everything I receive the same message but the error is always caused by a different entry number.
After the converting process is stopped by the error the new forum seems to have a lot of things converted but not everything. Browsing the forum I find some problems that disappear running the maintenance functions.
What can I do to avoid such converting errors?

[Marcosms]

I did a lot of tests and was able to import almost everything correctly but nothing to do with attachments.
No way to import them and no data in the attachments table.
I also did  lot of reading in this forum and I understand that the converter is made to work correctly with attachments but I can't have results and can't find answers.
At step 10 when converting I receive the duplicate entries error messages. Going to the next step the conversion is completed but without attachments at all. I did a lot of testing with different converting files but without results.
I've read that: "When converting attachments set the width and height for images" but I can't find where to insert such info.
Any suggestions on what to try to have the attachments converted?

[JayBachatero]

Try using the converter in this topic: YaBB SE 1.5.4