Cant publish posts with images

Hey guys

Basically the problem is whenever I attempt to create a new post with images in it throws up this error
Not Acceptable

An appropriate representation of the requested resource /wp-admin/post.php could not be found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

if I create a post with just writing and no images it will publish and everything is ok, ive read around a couple of feeds and found some possible solutions like:

Deactivating plugins then reactivating to see where error maybe occuring
Also checking to see if posts.php is in the appropriate directory

I have checked these and yet nothing, would it be possible to have some help?

Many thanks