The alpha 4 version of Subscribe to Comments 2.0 is now available. Upgrade if you were having problems. If you are using a cutting edge version of WP 1.5.1, it is a necessary upgrade, because of some recent file shuffling in SVN.
I’m still going to hold off publicly releasing a final version until WP 1.5.1 is out, because I don’t want to have to spend all my time supporting issues that are related to the bugs in WP 1.5
The only people who should be using this now are people who are comfortable running alpha WP 1.5.1 code.