I was compelled by Withoutabox to make an IMDB title page for my film in order to upload a trailer. Now my name appears across IMDB as two different people Thomas Altheimer (I) and Thomas Altheimer (II)
In your case, you'll need to go to the name page with the higher roman numeral (II) and submit a Name Correction or Merge. The name will need to be typed this way:
Altheimer, Thomas (I)
Since it looks like there is only one person with that name in the IMDb, after the update has been accepted, the roman numeral to the right of the name will be removed.
I hope this helps. Please write back if you have any more questions.