[Black Tiger]

In that case your hosting provider has protected these settings, he's probably using php fastcgi (php in cgi mode, mostly used in combination with phpsuexec).

Try doing the following. Instead of using a .htacces file, create a php.ini.
Put in there:
upload_max_filesize 30M
php_value post_max_size 30M

Try again. If this works but you get another error (timeout or security token missing), you can try and add this setting to the php.ini you made:
max_execution_time = 180
This increases the time to 3 minutes. If you have big files, it might be you have to increase this to a higher setting.

You could also add:
max_input_time = 180

The default of both these settings is 60. If you get an error again, then your hosting company has protected the possibility to use your own php.ini files too.
In that case the only solution is to contact your hosting company.