[miz]

can you give more info about your host ?
like php version and Os

also please check if php is under safe_mode
cuse some function dosent work with safe mode
to check use this script

PHP Code:

<?php 
// Check for safe mode
if( ini_get('safe_mode') ){
   echo "Safe mode is on";
}else{
  echo "Safe mode is off";
}

?>

if safe mode is on turn it off and try again
and please report.

edit :

YEP i was right chmod is disabled on safe mode

you can find all of functions that dosent work with safe mode
here

lets hope this is the problem.