After the upgrade on krishna, shoutstats was not updating the graphs. I'd suspected all along it was because rrdtool was not installed. Yesterday wanted to kill some time, so poked around krishna, found only librrdtool was installed, rrdtool itself was not, and was not available in the CD repository. rpmfind.net is your friend. Added the relevant ftp site there, and hey presto. (This skips the hour or so of dependency hell trying to download each package individually, not knowing what package contains the dependency (RRDp) - it was perl-rrdtool - and so on. Also took an hour to download the filelist from the slow rpmfind.net ftp site.)
Then I'd to go into the update.php and index.php and remove the hardcoded paths to rrdtool - probably added by us on the old krishna. Once that was done, working fine.