What really happened is that I had keyed in mpq rather than mpg. The underlined 'g' looks like a 'q'. Thanks. Right now I have a dependency problem as follows. The following packages have unmet dependencies: knemo: Depends: kdelibs4 (>= 4:3.2.3-3.sarge.1) but 4:3.2.3-2 is to be installed Seems like my current version is too too high for the package. Any suggestion? Jianan