Media Library Problem – can't insert images into pages or create a header

I’ve just installed WordPress 3.6 on the Bell host and am just starting a new website in the subdirectory of an existing website. I’ve created a child-theme for the Responsive theme and have added a little bit of text to see what it looks like. I’ve tried to add pictures though and have run into some problems. Any changes to the style.css were just to change font size and spacing.

When adding an image to a page it starts to load then I get an error: “an error occurred in the upload, please try again later”.
I look in the media folder and the picture is there unattached, and I look on my server and it is in the uploaded folder (three versions of the same picture in different sizes). I am able to use HTML to put it in the text on the page by referring to the upload folder directly which is tedious and from what I’ve read complicates things.

If I try to choose a custom header, the media library screen comes up blank as though there are no pictures in my library.
If I try and upload another picture I get the error: “an error occurred, try again later”
Because of this error I am also unable to set the featured image.

If I go to the Media Library tab, the pictures are there but I can’t attach them to anything
In the Media library I can add new pictures and edit them no problem

I’ve tried the following:

• updated automatically…. didn’t work
• Updated manually by deleting all files and folders except wp-content …. didn’t work
• added define(‘CONCATENATE_SCRIPTS’,false); to the wp-config.php file …. didn’t work so I changed it back
• file permissions for the upload folder are 700
• I’ve got all plugins deactivated – nothing started really because I’m just begining the website
• Bowser caches empty …. didn’t work
• I’ve tried the 2012 and 2013 themes … same problem on all other themes
• I’ve tried Firefox, Chrome and IE

Any help would be greatly appreciated. I’ve wasted so much time on this.
Thanks