Problem with Parked domains

[mat40]

Hello everybody,
I have problems with my parked domains.
I am using Fillezilla to upload my sites.
I bought 10 domain names to Godaddy.
Then, i bought the hosting solution to Hostgator, with a main domain.
Then, i parked my 9 others domains with their corresponding URL with "Parked domain maintenance" functionality of Hostgator.
I uploaded without any problems my first site, with Fillezilla.
Then, i tried to upload a second site, to its specific URL, always with Fillezilla.
But i had already there all the files of my first site.
If i delete these files (of the first site), they are also deleted in my first URL, where i uploaded the corresponding files firstly.
If i don't delete these files, and upload the files of the second sites, my second site has its own files and also the files of the first site.
So, i can only have one site presently.
After this, i looked at the ten URL adresses and all this sites shows the content of the first site, then i have uploaded only on the first URL.
I really don't know how to solve this problem...
Can you help me, please ?
I thank you very much. Best regards. Mat40.