htaccess is not working

[eluser]Blue Sapphire[/eluser]
Thanks for the guidance. I rolled back the changes in config file. The script begin to work properly with 'index.php' inclusion.
Then I placed following code in htaccess file.

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php/$1 [L]
</IfModule>
<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

RESULTS:
1- http://localhost/personal/dev/ci/ [Works Fine]
2- http://localhost/personal/dev/ci/index.php [Works Fine]
3- http://localhost/personal/dev/ci/index.php/myform [Works Fine]
4- http://localhost/personal/dev/ci/myform [Takes back to default WAMP SERVER page]

NOTE: I have created aliases in WAMP, so my script directory location is outside of WAMP 'WWW' directory.
My directory location for this script is 'E:\personal\dev\ci', whereas WAMP SERVER location is 'c:/wamp/www/
' .

Thanks in advance