While installing xine lib rpm I got following error msg>>
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[root@localhost MyDownloads]# rpm -iv xine-lib-1.0.0-0.14.rc5.1.fc2.fr.src.rpm
warning: xine-lib-1.0.0-0.14.rc5.1.fc2.fr.src.rpm: V3 DSA signature: NOKEY, key ID e42d547b
xine-lib-1.0.0-0.14.rc5.1.fc2.fr
warning: user machbuild does not exist - using root
warning: group machbuild does not exist - using root
warning: user machbuild does not exist - using root
warning: group machbuild does not exist - using root
[root@localhost MyDownloads]#
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Can ne1 explain this?

Those are warnings. No problem unless the files have been compromised. The key thing is supposed to verify that the file is identical to the one the creator originated.