at last it work great, i know where was my error. For those who are getting the error:
Downloading ....

Warning: fopen(/home/desi/public_html/phpuploader/files/) [function.fopen]: failed to open stream: Is a directory in /home/desi/public_html/phpuploader/includes/functions.php on line 173

Could not download for an unknown reasonDownloading ....

Warning: fopen(/home/desi/public_html/phpuploader/files/) [function.fopen]: failed to open stream: Is a directory in /home/desi/public_html/phpuploader/includes/functions.php on line 173

Could not download for an unknown reasonExtracting downloaded files...
Could not extract. Delete everything in the 'files' folder and re-run the script.
In the config.php edit Server Config line for;
$path - its only the path where you have uploaded phpuploader

example:
/home/desi/public_html/phpuploader/

----------

$filespath - its the path where the file will be downloaded
example:
/home/desi/public_html/phpuploader/files/


That's it, should work file