a. Kevin Adey reports "I get a system error, "Finder - Unimplemented trap," when I try to close the box where you add/remove applications." Bill Brown had essentially the same problem.
Update: Drag original files instead of aliases. This should avoid the system error - according to both Daryl Cornutt and Adam Martin.
b. Jake Plotkin found that it caused problems accessing servers through aliases listed in the Recent Servers folder. Jay Duff had a similar problem: "Once PPP menu was installed, I hard lock every time I try to connect to an AppleShare File Server or a shared Mac."