uploads failing on plesk server

I’m having an issue with using the wordpress console to upload anything. i’ve tried upgrading, installing plugins and uploading photos and none of it will work. i get this message when trying to install a plugin: “Unable to locate WordPress Content directory (wp-content)”, this one when i try to upgrade: “Unable to locate WordPress Root directory”, and when i try to upload a photo using NextGen Gallery (which i installed via ftp), it says “contains no pictures”. I can manage everything else, i just can’t upload. I’m starting to think it has something to do with plesk. anyone have any ideas what i can try? this is driving me crazy. thanks!