SOLVED:
After scouring the forums, I found a post that said the cause of this error is most likely from the 1099B upload. TurboTax asks you to upload a copy of that document to verify the info you entered. Here's what I did exactly:
1. Found the 1099B section (in my Federal return)
2. Pressed edit, and then went to the section where it showed my uploaded document
3. Delete that upload
4. Open the document you sent on your computer in Acrobat Reader
5. RESAVE it as a PDF
6. Upload the NEW pdf to your 1099B section.
7. Save that edit. And re-file.
That was it. I honestly don't know why it didn't like the first pdf I submitted, I'm not a coder or anything. But this worked. My e-file was very quickly approved after submitting this time.
