I know the subject of this post is very vege but cant really see any other way of putting it. When I sync stuff onto my PC all the folders are blank. When I look at the web interface files seem to be there but when I click on file I get this type of thing.
if you would provide more information it could lead to finding a solution for your problem. The error you are describing is a very general one. A log output would help for example with the exact error message.
Dropbox / ownCloud - You should choose the one you are most comfortable with.
If the configuration and maintenance of the server is too much work for you, you could try our appliance. It works out of the box, you just need to import it in the visualizer of your choice.