My story: I followed Jeremy's advice and ever so slightly chipped the white plastic piece. (Note: the little hook that slides in the channel is VERY fragile!)
Not willing to give in to defeat, I then removed the side panel. It's only one screw, accessed in the back of the machine. Pull the duplex cover down and you'll see the one screw that holds the left side panel on. After removing the screw, carefully unclip the other connections. I found it easier to remove the panel when I let the side of the machine dangle off the edge of the workbench.
Once open, I pushed the lever back in place and made sure the spring is attached properly. Positive test!!!
For now, the printer is working great again. (And yes, it is a workhorse.)