The same issues like this: http://drupal.org/node/590944

The warning theme_imagefield_crop_widget() expected to be a reference pops up when i switch to php 5.3 under drupal 6.14.

sites/all/modules/imagefield_crop/imagefield_crop_widget.inc: Line 89;
Original:
function theme_imagefield_crop_widget(&$element) {
Modified:
function theme_imagefield_crop_widget($element) {