I have not used Net::FTP in years, i remember nothing about it's API ... but sincei was bored i skimed your post, saw that the error was coming from the "get" method and read the perldocs. it appears you are calling it incorrectly -- it can take 3 args, and the third arg is refered to in the docs as "WHERE" but it is not a directory name...

If WHERE is given then the first WHERE bytes of the file will not be transferred, and the remaining bytes will be appended to the local file if it already exists.

...The error message being returned seems to be the FTP server complaining that it can't understand the "REST" command since it specifies a string instead of an int for the number of bytes to skip (a quick google search indicates that i am probably correct, "REST" is hte low level FTP command indicating that the next command only wants the "rest" of the file after so many bytes.