I'm a huge fan of your script. However, after updating to MM4, I experienced some major problems while using it.
The play counts for most of the previous weeks are different now after updating. So for example, the script recorded a play count of 105 for the week before updating and now in MM4 it suddenly says that the play count was 95. This is true for most of the weeks in 2011, as far as I can tell.
In addition, the columns in your script's nodes don't match my usual setting any more, which is kind of unsatisfying.
I hope you're planning on updating your script because it is a truly brilliant piece of work I would not wanna miss!
I think I have discovered the main problem:
It seems as if your script and my library are in two different timezones
For example, when playing a song, MM says "Last Played: Today, 08:14" but when checking the same song in the "Browse History" node, it says it was last played at 07:14. I checked some more songs and it's always the same.
As far as I can tell this pretty much explains the differences in play counts after updating to MM4
Hope this helps