FTP "an error has occurred"

[kafka]

Anyone have any ideas why this error may pop up?
Any input would be greatly appreciated.

Code:

The error occured in file /var/www/ispcp/gui/tools/filemanager/includes/filesystem.inc.php on line 64.
function ftp_openconnection (/var/www/ispcp/gui/tools/filemanager/modules/browse/browse.inc.php on line 234)
function net2ftp_module_printBody (/var/www/ispcp/gui/tools/filemanager/main.inc.php on line 313)
function net2ftp (/var/www/ispcp/gui/tools/filemanager/index.php on line 61)
argument 0: printBody