Views2 Handlers: Fatal Error Class 'views_handler_field' not found
Is your class code in the same file as your hook, aka the .module or .views.inc file? That doesn't work because views_handler_field is in a separate file and only loaded when required.

You need to move it in a separate file which as the same name as your class and the ending ".inc", inside the folder that you defined in 'path'. (in your case, your module directory, for large modules with many files, it's recommended to place them in a views directory)

Then, views will automatically include your class including the file that contains views_handler_field (because you defined the parent relationship in your hook) when required.