Can not edit the widgets

I run a few WP sites on multi servers. One of my clients which I run his site on a WP friendly server asked me to change/update a picture that is placed in the side bar via a widget. Heck simple right, for the life of me I can not change or edit any of the sidebar pull downs bars, the system will not allow me to open the sidebar to edit, add or delete a widget. I checked write permissions, I changed browsers, I turned on and off java, I updated java, I upgraded to WP 3.03 I even changed sites to see if it was the server or WP that was causing this problem. Everything seamed ok on my server till I checked a different site this morning and I was locked out of editing the widgets. Now I checked another on my server and everything is fine…..

Anyone have any idea what is wrong?

Thank you for your time