paperclip plugin not working on windows

the paperclip works on ubuntu but on windows it gives an some error.
the error is
" There were problems with the following fields:
Avatar C:/DOCUME~1/ozone/LOCALS~1/Temp/Water lilies,2700,0.jpg is not
recognized by the 'identify' command.
Avatar C:/DOCUME~1/ozone/LOCALS~1/Temp/Water lilies,2700,0.jpg is not
recognized by the 'identify' command "

any idea ??
i'm almost stuck here

thanks