.htaccess upload_max_filesize php_value

Hi ,
I m PHP 5.2.0 / Apache
and I can't access php.ini

I try to update .htaccess
and added
php_value upload_max_filesize "25M"
php_value post_max_size "25M"

However it will give me "Internal Server Error"

>From the log file , i can see the error msg

[Mon Jan 22 14:57:57 2007] [alert] [client 127.0.0.1]
C:/work/www/Joomla-1.0.11_eCommerceEdition_VM-1.0.7/.htaccess: Invalid
command 'php_value', perhaps mis-spelled or defined by a module not
included in the server configuration, referer:
http://joomla/administrator/index2.p...section=config

so I searched on web and try again.. and update the .htaccess

<IfModule mod_php5.c>
php_value max_execution_time "60"
php_value upload_max_filesize "25M"
php_value post_max_size "25M"
</IfModule>

No Error msg, but nothing change.

then I searched again ....

updated php code - ini_set()

print "b4 ".ini_get('upload_max_filesize');
ini_set("upload_max_filesize" , "10M");
print "<br/>after ".ini_get('upload_max_filesize');

which I got the same "2M" from the php code

anyone have any idea where should I go ? is this php5 problem ?
or i did something wrong ?

I have following setting in httpd.conf
<Directory />
Options +FollowSymLinks
AllowOverride All
</Directory>

actually I try following configuration in my local machine and ISP,
both didnt work
<IfModule mod_php5.c>
php_value max_execution_time "60"
php_value upload_max_filesize "25M"
php_value post_max_size "25M"
</IfModule>

any idea ? [however mod_rewrite is working fine]