he gave me the server details and guess what.
he is using , domain1.com/drive to install my product , but ftp was for ; domain2.com/file ,
and later he emailed me that , he want it to be installed on domain2.com/file not on domain1.com/drive ,
so now i did install with very normal process as all the users should install my product , and vollaaaa , it is working without any problem.
He installed it the way it will never work. htaccess and system’s configuration was conflicting , as he was doing these kind of strange configuration things , and was blaming the product that it has bugs.