Error saving media attachment.

Hello everyone,
I’m trying to upload photos and this is the message I get.
If using multiple files uploader, I get the following message:

“xyz.jpg” has failed to upload due to an error
Unable to create directory wp-content/uploads/2013/07. Is its parent directory writable by the server?

All folders in the website have 755 permissions. I also tried 777, nothing changed.
I’ve read on another thread other users are experiencing a similar problem (though they get slight different messages.

Also, don’t know if this is related, it couldn’t install a theme on its own, I had to download it, upload it and then activate it from the dashboard. Felt like mentioning it since it’s same wp-content folder.

I’m not skilled in code programming, so pls if you do come up with something, try to be a little more detailry than you would normally. ?? Thanks a lot!