I can import file to Main Server . But i can't import file to File Server. And get this error :

Error happened:
Software error:

cant open file at Modules/XUpload.pm line 91.

Hello admin,
I try to import files to my File Server. And i get this error:

Error happened:
Software error:

cant open file at Modules/XUpload.pm line 91.

My site is license site.
Can you help me to solve this error ?

Hello admin,
My customers are requesting FTP feature on my site. So do you have any mod or plugin for this feature?