For VBScript output to work, you may need to percent-encode the destination path twice. Like this.
Regular FTP path:
ftp://username@yourcompany.com:password@server.com/file.m3u8?passive=yes
Single URL (%) encoded – used for some standard FTP configurations
ftp://username%40yourcompany.com:password@server.com/file.m3u8?passive=yes
Double URL (%) encoded – used for VBScript FTP
ftp%3A%2F%2Fusername%2540yourcompany%3Apassword%40server.com%2Ffile.m3u8%3Fpassive%3Dyes