I had the same error message. I had installed the three packages xulrunner-1.9, xulrunner-1.9.1 and xulrunner-1.9.2. I removed all xulrunner packages except xulrunner-1.9.2. Still no go.
Then went into the directory /etc/gre.d. There were (among others) two files named "1.9.1.9.system.conf" and "1.9.2.3.system.conf.dpkg-bak". After I removed the first and renamed the second to "1.9.2.3.system.conf" prism worked.
I had the same error message. I had installed the three packages xulrunner-1.9, xulrunner-1.9.1 and xulrunner-1.9.2. I removed all xulrunner packages except xulrunner-1.9.2. Still no go.
Then went into the directory /etc/gre.d. There were (among others) two files named "1.9.1. 9.system. conf" and "1.9.2. 3.system. conf.dpkg- bak". After I removed the first and renamed the second to "1.9.2. 3.system. conf" prism worked.