Warning when using ordinary filefield widget after uploading with mupload.
Tho, I can use filefield widget and upload files before I use mupload.

The error I get is:

Warning: filesize() [function.filesize]: stat failed for temporary://p16hdg4pcokje2v4lroval32bj.tmp i mupload_file_save_upload() (row 409 of sites/all/modules/mupload/mupload.module).

The file temporary://p16hdg4pcokje2v4lroval32bj.tmp could not be copied because there was no file with that name... (translated)

Maybe it has something to do with this: http://drupal.org/node/1226786