Declaring variables from the url

PHP list, I have many times set the value of a variable by declaring it in the URL, like so: http://www.domain.com/index.php?var=1 And then, to use the variable, all I have to do is use it in the script, like so: echo "This is the value of the variable: " . $var; But, for some reason, in a script I'm writing now, this simple process isn't working. The only thing I can think of that is different between before and now is that the new script is being executed in PHP5, whereas before was with PHP4. In my new script, I check the value of $_SERVER['QUERY_STRING'], the value is contained in there, so it is being assigned and contained somehow. What could I possibly be missing in what should be a super simple process? -- Dave M G