Help! Product CSV File Upload Error: Validation failed: The variant 'Default Title' already exists.

[RetroArt]

I'm trying to upload a CSV file with 25 products; there are no options/variants for the products but most of the products do have more than one image. On my first attempt, 14 products of 49 uploaded successfully, but I cannot upload the remaining 35. I get the "Validation failed: The variant 'Default Title' already exists." for every line. The current file is formatted EXACTLY the same way; all I did was delete the rows with the successfully uploaded products. Anyone have a solution??