Hard to find his predictions for 2002, the last midterm.
But I did!
http://64.233.161.104/search?q=cache:5CkQhvTEYcMJ:www.pkblogs.com/quasipundit/2002_11_03_quasipundit_archive.html+2002+sabato+results+%22house+seats%22+republicans+-2006&hl=en&gl=us&ct=clnk&cd=7
"Sabato has gone from +1 Democrat in the Senate to no change. Thanks to Dodd's post for pointing that out. Sabato also went from +3 Republicans in the House to +4. As close as this election is, those "tweaks" are epocal."
The actual results were:
+2 Republicans in the Senate
+6 Republicans in the House
So his average error was about 100%
No surprise these predictions are no longer on his site LOL!
Good catch!!!