I have noticed several of these in the last couple of days. In this case, it is 24 minutes of computing time and 67.4K shares not paid. Tycho, can you please explain?
Looks like you weren't submitting shares for this block.
Look at the line before the last one - this reward is lower too, so you resumed your work during this block.
EDIT: I checked my log files, no shares were received from you between 22:34 and 23:28 UTC, it means that you had some connection problems or hardware lockup.
Some users can see this situation when their miners are temporarily switched to PPS mode. Pay-Per-Share reward is not connected to blocks and it not shown in blocks statistics. (But in this case it's not the reason).
There were no network issues on my end during that time (I VPN all day and was doing a lot of Netflix streaming recently]. Because of my intense use, Comcast has bent over backwards delivering me a good connection. No errors on my modem, router or machine. So, there was a network issue somewhere between your network and mine. Further, the block count on my client showed more were accepted than your page. So, I am not sure what is going on (internet, deepbit ISP?, deepbit), but doing free work is not my style. I have switched pools for now and haven't noticed any problems with slush even though it is much more difficult to see since those stats are not on his page. My client has not given any more connection errors.
For Slush: I don't consider switching to your pool a downgrade by any means, I was just getting used to being able to see the stats directly on the deepbit site and was still looking at long polling results [still never made a 1% difference, but I would love to see it in your pool].