Variables not working!

Hi, I am new to PHP scripting and struggling with the following problem. I have two files, an HTML file and a PHP file. HTML file contains a form with one text field and a submit button. When a user pressed the submit button, it calls the php file (<form action="test.php" ...>). What the php file does is just echo back the text received from html file to the user again. Name of the text field is 'fname'. When I used this variable in the php file (as $fname) it does not contain the value of the text field. Query-string appended to the url during the submission is also correct. I checked for all syntax errors, but the codings are perfect. Do I have to change php.ini file to fix this problem. Could anyone can help me to solve this problem. Kaushan