I have released WP-PostRatings 1.61  which fixes a code injection via “HTTP Referrer” and affects users who are on WP-PostRatings 1.50 only. This is the same code injection fixed for WP-Polls few days back.
I have checked the rest of my plugins to ensure that the code is not in anymore of my plugins. Sorry for any inconvenienced cased.
Similar to WP-Polls, I also took this chance to port the readme.html to the proper readme.txt which WordPress.org is using and now you can see all the details of WP-PostRatings  right from the plugins page itself regardless if it is from your WP-Admin or WordPress.org.
All users should upgrade now
Props to Dion Hulse aka dd32 for the report!
Download: WP-PostRatings 1.61