You have to upload the app/ folder of 2 extensions the HelloThemes one and the HelloUpload. (always merging the folders)
Once you upload both extensions you disable cache and should see the new hellothemes module between the option CMS and Reports.
That last error you are receiving it's because it can't find this file:
If you copied the hellothemes extension it should be there. Check if you have it or merge the folders again.
Tell us how it went!