"Enforce crop box ratio" causes server error 0 for Firefox 3.6

Here's the steps to repeat for me:

1. Download the latest 6.x-1.x-dev
2. Create a filefield with "Imagefield with crop" as the widget type
3. Accept the defaults for the field which leaves "Enforce crop box ratio" checked
4. Attempt to upload an image
5. The browser returns:

An HTTP error 0 occurred.
/filefield/ahah/image_asset/field_imagefield/0

If I then hit "Save" on the node it will forward my browser to filefield/ahah/image_asset/field_imagefield/0 and return a Json array like:

{ "status": true, "data": "\x3cdiv id=\"edit-field-imagefield-0-ahah-wrapper\"\x3e\x3cdiv class=\"form-item\" id=\"edit-field-imagefield-0-wrapper\"\x3e\n \x3clabel for=\"edit-field-imagefield-0\"\x3eImage: \x3c/label\x3e\n \x3cdiv class=\"filefield-element clear-block\"\x3e\x3cdiv class=\"widget-preview\"\x3e\x3cdiv class=\"jcrop-preview-wrapper\" style=\"width:200px;height:150px;overflow:hidden;\"\x3e\x3cimg src=\"http://closets/closets/sites/default/files/screenshot_038_6.png.crop_display.jpg\" alt=\"jcrop preview\" title=\"\" class=\"jcrop-preview\" /\x3e\x3c/div\x3e\x3cscript type=\"text/javascript\"\x3ejQuery.extend(Drupal.settings.imagefield_crop, { \"edit-field-imagefield-0\": { \"box\": { \"ratio\": 1.33333333333, \"box_width\": 500, \"box_height\": 500 }, \"minimum\": { \"width\": \"200\", \"height\": \"150\" }, \"preview\": { \"orig_width\": 708, \"orig_height\": 491, \"width\": 200, \"height\": 150 } } });\x3c/script\x3e\x3c/div\x3e\x3cdiv class=\"widget-edit\"\x3e\x3cinput type=\"hidden\" name=\"field_imagefield[0][fid]\" id=\"edit-field-imagefield-0-fid\" value=\"33\" /\x3e\n\x3cinput type=\"hidden\" name=\"field_imagefield[0][data][crop][x]\" id=\"edit-field-imagefield-0-data-crop-x\" value=\"0\" class=\"edit-image-crop-x\" /\x3e\n\x3cinput type=\"hidden\" name=\"field_imagefield[0][data][crop][y]\" id=\"edit-field-imagefield-0-data-crop-y\" value=\"0\" class=\"edit-image-crop-y\" /\x3e\n\x3cinput type=\"hidden\" name=\"field_imagefield[0][data][crop][width]\" id=\"edit-field-imagefield-0-data-crop-width\" value=\"654.666666667\" class=\"edit-image-crop-width\" /\x3e\n\x3cinput type=\"hidden\" name=\"field_imagefield[0][data][crop][height]\" id=\"edit-field-imagefield-0-data-crop-height\" value=\"491\" class=\"edit-image-crop-height\" /\x3e\n\x3cinput type=\"hidden\" name=\"field_imagefield[0][data][crop][changed]\" id=\"edit-field-imagefield-0-data-crop-changed\" value=\"1\" class=\"edit-image-crop-changed\" /\x3e\n\x3cdiv class=\"form-item\" id=\"edit-field-imagefield-0-cropbox-wrapper\"\x3e\n \x3clabel for=\"edit-field-imagefield-0-cropbox\"\x3eCrop area: \x3c/label\x3e\n \x3cimg class=\"cropbox\" id=\"edit-field-imagefield-0-cropbox\" alt=\"\" src=\"http://closets/closets/sites/default/files/screenshot_038_6.png.crop_display.jpg?1273260920\" /\x3e\n\x3c/div\x3e\n\x3cinput type=\"hidden\" name=\"field_imagefield[0][list]\" id=\"edit-field-imagefield-0-list\" value=\"1\" /\x3e\n\x3cinput type=\"submit\" name=\"field_imagefield_0_filefield_remove\" id=\"edit-field-imagefield-0-filefield-remove\" value=\"Remove\" class=\"form-submit\" /\x3e\n\x3c/div\x3e\x3c/div\x3e\n\x3c/div\x3e\n\x3c/div\x3e\x3cscript type=\"text/javascript\"\x3ejQuery.extend(Drupal.settings.ahah, { \"edit-field-imagefield-0-filefield-upload\": { \"url\": \"/closets/filefield/ahah/image_asset/field_imagefield/0\", \"event\": \"mousedown\", \"keypress\": true, \"wrapper\": \"edit-field-imagefield-0-ahah-wrapper\", \"selector\": \"#edit-field-imagefield-0-filefield-upload\", \"effect\": \"fade\", \"method\": \"replace\", \"progress\": { \"type\": \"throbber\" }, \"button\": { \"op\": \"Upload\" } }, \"edit-field-imagefield-0-filefield-remove\": { \"url\": \"/closets/filefield/ahah/image_asset/field_imagefield/0\", \"event\": \"mousedown\", \"keypress\": true, \"wrapper\": \"edit-field-imagefield-0-ahah-wrapper\", \"selector\": \"#edit-field-imagefield-0-filefield-remove\", \"effect\": \"fade\", \"method\": \"replace\", \"progress\": { \"type\": \"throbber\" }, \"button\": { \"field_imagefield_0_filefield_remove\": \"Remove\" } } });\x3c/script\x3e" }

If I disable "Enforce crop box ratio" then the error goes away and the file can be uploaded and cropped just fine in Firefox.

It works in Chrome regardless of this setting.

I can create a node in Firefox by selecting the image but not "Uploading" it and then hitting the "Save" button on the node. Then I can edit the node and the cropping tools work fine.