moving domain from windows server to linux server

[Kanagaraj]

We have backup one site in our windows 8.1 plesk server to our ftp backup server. when we restore to our CentOs4 plesk 8.1 server from our Backup FTP server the backup files shows "not a Backup File". the problem is only in using FTP Server.

How can we solve this and moving windows server to Linux server

Thanks
Kanagaraj