the header image will not change

I have read through the how to and looked though the list of others with the same issue as me – but I cannot ascertain a resolve.

I click upload to put my image on to a theme (any theme, I have tried this on 4) and instead of going to the ‘crop’ page it goes directly to the manage themes page… with no clarification as to why ??

A few areas on the site have suggested that this is permissions but I cannot seem to sort anything. I’m on my 3rd day and ready for putting wordpress back in its box!

Please help