Cannot access wp-admin – Image links all broken

I installed the atahualpa theme earlier today, and spent most of the day configuring it. The last thing I did was go to the ‘General’ settings (as instructed in the theme) in WordPress to change the subtitle(?) and links there as I wanted links to my main website, and after hitting save the screen went blank for a second, then went to a 404 page not found. Havent been able to access admin since then(same 404 error). Tried deleting and reloading the entire wp-admin directory to no avail.

The blog itself shows up;

but all image links are broken.

I hate to reinstall again as it would be the third time in as many days. Any ideas? Thanks in advance..

Mark