Hi,
I try to edit the activity, its prompt the error. 'columns[....].sources' is null or not an object.
I had a similar error, and was ultimately not able to fix. If you want to see the activity form, select no when asked about the debugger, and the form should come up.
I believe the problem is that some windows library is corrupted. I also noticed an issue where the stock market chart at the top of the WSJ site would not display, and connectpress.com would not accept my password. These errors occurred in IE, Firefox, and Safari.
To fix, I ended up reloading an older system backup.
Tom