HTTP_POST_VARS truncated

Hello, To test the http/php setup on one of my computers I wrote a very simple html form, with two select fields, two text fields, and the submit field. Pushing submit the data are sent via POST method to an extremely simple PHP page which only contains something like: foreach (var, key) in HTTP_POST_VARS { print "VAR: $var KEY = $key } It works, (meaning that php code is correct, html output is displayed, and no error are reported) but only prints three lines, i.e. the two select fields are missing. Both the php and the html code are syntactically correct: I double checked that on the books, just to be sure. It looks like the select fields, and them only, are not passed to the form by the server, or that in some other way they never make it into HTTP_POST_VARS. Any ideas? Setup is plain Red Hat 7.2 with its default apache/php packages. TIA, mweb