When the Secure FTP Task does not work as expected, it may be necessary to have the task generate a log to help identify where the issue is occurring.
While in the Control Flow of the package in Visual Studio, single click on the Secure FTP Task to select it. Then hit F4 to display the Properties window. Under the MISC section, in the LogFileLocationproperty put in a fully qualified file path and name. Then the next time the package is executed a file with the name specified will be created in the directory specified. This file can then sent to Support for analysis.