Thread:Project:Support desk/Image upload problem in a new installed Mediawiki 1.21.1

I'm a newbie in mediawiki and hope someone can help me with this problem i never had before with older versions. After instal all seems ok but uploading Images give a problem, i get this>>> Error creating thumbnail: It was not possible to store the thumbnail file on the target location. Also the image does't show on de page where its used. I hope for some help.