Uploading your GEDCOM will not create any profiles. You have to process each profile via the GEDCOMpare process.
When you edit an existing profile that matches a profile in your GEDCOM, you will be able to assess the information for the profile and decide whether or not to add the information to the existing profile.
When you create a new profile, you will be able to do the same assessment of your GEDCOM's information for the individual.
So, essentially, you control the errors.
Tip: if you haven't used the GEDCOMpare process yet, start with a very small chunk of your GEDCOM - I seriously mean no more that a dozen or so profiles. You will probably have to split your GEDCOM to create the small chunk.
Post back to this thread if my comments are not clear or if you need additional help figuring how to use GEDCOMpare or to split your GEDCOM.