newbie problem working with Forms - undefined constant?

Hi, I've really only been using PHP for three weeks though so bear with me if this sounds a bit daft. I have some scripts which piece together to build a message board with a mysql database. The scripts come from the SAMS book - Teach Yourself PHP in 24 hours (ch. 23). On one of the pages is a form which extracts the users details and logs them into the database when they join - but I receive errors such as : Warning: Use of undefined constant password - assumed 'password' in c:\program files\apache group\apache\htdocs\mysql\join.php on line 11 I have the value of each input box as form[login], form[password] etc.. and it seems to be tripping over these. Can anyone shed any light on this problem? I can send the code if it may help? Cheers in advance, Phil