500 internal server error in joomla ckeditor

I have installed ckeditor in my joomla and it's working fine, except the uploading section. I got an error message

500 internal server errors The request was not completed. The server met an unexpected condition.

mydomain/plugins/editors/ckfinder/core/connector/开发者_开发百科php/connector.php?command=QuickUpload&type=Files&CKEditor=text&CKEditorFuncNum=1&langCode=en (port 80)

while I am trying to upload a document. Also get this error message in the image uploading section. Does any one have an idea?