Unfortunately, Scribd has a very specific policy in regards to removing plagiarised works, so I have PM'd the two authors on FFN that have that option available, and left a review for the other on the affected story.
This is where this gets weird.
While I was unable to find matches for every story, it appears that one of the stories posted by Invader Zim Fanatic was plagiarised by 27cowboys Invader Zim Fanatic uploaded Textually Active on 2009-07-12. 27cowboys uploaded the same: Textually Active on 2010-01-26.
Given that 27cowboys is in the US and Invader Zim Fanatic is in France per their profiles, I'm not of the opinion that they are the same individual. I highly doubt that Textually Active belongs to IZF, but I was unable to find another match for the piece to determine it's original author.[Screens]
Given the oddity here, I did not post this to TaPiR.