unexplained accessed denied on settings update

For the past day - whenever I update any information within drupal's admin area, the system displays an 'access denied' page.

- This behavior only started in the past day.
- The requested changes occur despite the errant access denied page display.
- The problem occurs during nearly any settings modifiction operation.

(some potential culprits)
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I have been trying out the various node security modules.
I have installed and used node_privacy_byrole.module.
I uninstalled it after discovering that it disables acidfree's ability to add photos.

(I like node_privacy_byrole.module. except for acidfree incompatibility)

I then tried organic groups but uninstalled that because it doesn't seem to provide the granularity I want.
I uninstalled organic groups.

Not longer after these uninstalls the problem described above started to occur.

spritefully yours