The user doesn't have permission to create a directory in the 
default login directory of their remote server. Since there's no FTP 
call to get a server's time, Dreamweaver must create a directory 
and read the server's timestamp to establish the time difference. 
This allows Dreamweaver to complete functions that involve 
comparing files' timestamps. 

Solution 
In order for for Dreamweaver's timestamp-related functions to work 
correctly, users must have permission (set by the Server 
Administrator) to create directories in the default login directory.