CakePHP 1.3.7 - Renaming className in Model file breaks login page

I have an install of Cake 1.3.7 which I inherited from a previous developer for one of my clients. There is a model that includes the following:

var $belongsTo = array(
[. . .]
    'TimeSlot' => array(
        'className' => 'TimeSlot',
        'foreignKey' => 'time_slot',
    ),
[. . .]

I have renamed this model and class to OtherInfo, and changed the foreign key to other_info. All the appropriate files exist, the cache files have been refreshed, and I've successfully tested everything. The code above now looks like this:

var $belongsTo = array(
[. . .]
    'OtherInfo' => array(
        'className' => 'OtherInfo',
        'foreignKey' => 'other_info',
    ),
[. . .]

Everything works fine, until I log out of the software. At that point, the login page fails to load. Instead it gives me a generic "An Internal Error Has Occurred" message, which assigning a debug value in config.php doesn't seem to help with. However, if I rename className back to TimeSlot, the login page will load and I can log in. Once I'm logged back in, I can then rename className to OtherInfo again and the rest of the software will work just fine.

So I know exactly what line of code is causing the problem, but not why it causes a problem or what to do about it. Does anyone have any advice? I am a total novice in Cake and consider myself having done well for getting this far.

It turns out the solution is to delete the contents of the cache directories so that Cake can rebuild them. These directories are in app/tmp/cache/persistent/ and app/tmp/cache/models/