Move file in Drupal 6 I am using drupal 6 as i am trying to save file that comes from another server through Json format 

I am using 

file_move('path of image','sites/default/files');


I also tried this  one Still having same error

file_move('path of image','sites/default/files', $replace = FILE_EXISTS_RENAME));


But it gives this error 


  Fatal error: Only variables can be passed by reference in


How to solve this? Anybody have idea ?

Thanks
Your First argument must be a variable. The file_move() documentation says: 


  $source: Either a string specifying the file location of the original file or an object containing a 'filepath' property. This parameter is passed by reference and will contain the resulting destination filename in case of success.