MySQL Text type failure

This is very peculiar -- I am using (I am using MySQL 5.0.27-
community) If I create a table with the following schema.....

CREATE TABLE `associates` (
  `id` int(11) NOT NULL auto_increment,
  `username` varchar(16) NOT NULL default '',
...
...
  `tstamp` timestamp NOT NULL default CURRENT_TIMESTAMP on update
CURRENT_TIMESTAMP,
  PRIMARY KEY (`id`),
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=27 ;

things in AS work swimmingly. However, if I add a column (anywhere in
the table, here I am just putting at the end) that is a text type,
call it `notes` (or even make, say varchar(500) ) as follows:

CREATE TABLE `associates` (
  `id` int(11) NOT NULL auto_increment,
  `username` varchar(16) NOT NULL default '',
...
...
  `tstamp` timestamp NOT NULL default CURRENT_TIMESTAMP on update
CURRENT_TIMESTAMP,
  `notes` text NOT NULL,
  PRIMARY KEY (`id`),
) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=27 ;

When I go to do an edit on the table, regardless of whether I add any
data to the notes field or not, and I save it, It won't come back up
when I go to edit it again (I get a 500 error). It saves the values
into the db correctly when I go directly into the db and look at the
changes -- but it wont come back up when I go to edit it without
generating
a 500 error.

I am using the latest version of Rails (2.3) , Ruby and
ActiveScaffold. Has anyone
experienced anything like this trying to use a large text field with
MySQL ?
thank you, Janna B

Never heard of that happening - can you post a stack track from the
log where it gets the 500?

--Matt Jones