Rails 3 Paperclip issues - ruby-on-rails

Question

i'm using Rails 3 and paperclip to upload some pictures.
However, each time i want to upload some pictures, if i perform a
new_picture.valid?
it returns me false.
I installed imageMagick and set the path in my windows environment variables.
But here is a problem, i'm using thin server, and in the console it return me a message when i try to upload the pictures:
I'm French, it returns me
"Paramètre non valide - /Users"
In english : "Invalid Parameter - /Users"
Here is what my image parameter contain:
"image"=>[#<ActionDispatch::Http::UploadedFile:0x5770710 #original_filename="Desert.jpg", #content_type="image/jpeg", #headers="Content-Disposition: form-data; name=\"service[service_pictures][image][]\"; filename=\"Desert.jpg\"\r\nContent-Type: image/jpeg\r\n", #tempfile=#<File:C:/Users/XXX/AppData/Local/Temp/RackMultipart20140210-2252-3r9p4g>>]
I think that the problem is located in where the tempfile is placed : "C:/Users/...
Because i'm french, on my computer C:/Users is named C:/Utilisateurs
Do you think that due to this ImageMagick would not be able to find the tempfile and so unable to perform its actions on it?
Here are my logs
Command :: identify -format '%wx%h,%[exif:orientation]' "C:/Users/Fred-Dev/AppData/Local/Temp/Desert20140210-2252-jpumkw.jpg[0]"
Command :: identify -format %m "C:/Users/Fred-Dev/AppData/Local/Temp/Desert20140210-2252-jpumkw.jpg[0]"
Command :: identify -format %m "C:/Users/Fred-Dev/AppData/Local/Temp/Desert20140210-2252-jpumkw.jpg[0]"
Command :: identify -format %m "C:/Users/Fred-Dev/AppData/Local/Temp/Desert20140210-2252-jpumkw.jpg[0]"
Command :: convert "C:/Users/Fred-Dev/AppData/Local/Temp/Desert20140210-2252-jpumkw.jpg[0]" -auto-orient -resize "x144" -crop "145x144+23+0" +repage "C:/Users/Fred-Dev/AppData/Local/Temp/Desert20140210-2252-jpumkw20140210-2252-1fia7d"
[paperclip] An error was received while processing:
Paperclip::Error: There was an error processing the thumbnail for Desert20140210-2252-jpumkw>
Have you any idea on how i could solve my problem?
Thanks in advance for the help
best regards
RESOLVED
In fact in the windows environment variables, you have to place the path to imageMagick in FIRST, before the windows one.
It's now working properly for me!