Escaping characters won't work

Hello, I'm running Apache 1.3.26, PHP 4.0.5 and WinXPpro. My problem is as follows: Try to execute this code: if (ereg[^0-9], $num)) print "That's not a number!"; result: parsing error, expects ')' on the if-line. Have also tried other expressions where I escape characters. They won't work. When I write: echo "HELLO \n"; echo "WORLD"; I get: HELLO WORLD (on one line!?) Anyone know what's wrong? Do I need to install an extension? Bottom of my httpd.conf: LoadModule php4_module c:/php/sapi/php4apache.dll AddModule mod_php4.c AddType application/x-httpd-php .php AddType application/x-httpd-php-source .phps Thanks, Lars