Unable to edit cms widgets

[RichieBoy67]

This problem has me baffled and has for a long time. I really cannot think of anything else to try.

When trying to edit/configure cms widgets the black box pops up and appears to load but eventually just disappears.

Here is what I have tried in order to fix it.

# - Disabled plug ins
# - Tried Standard urls/disabled htaccess
# - Uploaded fresh Vbulletin files and re-ran upgrade script
# - Have tried multiple browsers
# - Removed Plug Ins with possible connection

What am I missing here?

Thanks,
Rich