XScreensaver requires too many dependencies: # rpm -qR xscreensaver xscreensaver-base = 1:5.08-9.fc11 xscreensaver-extras = 1:5.08-9.fc11 xscreensaver-gl-extras = 1:5.08-9.fc11 rpmlib(FileDigests) <= 4.6.0-1 rpmlib(PayloadFilesHavePrefix) <= 4.0-1 rpmlib(CompressedFileNames) <= 3.0.4-1 xscreensaver-gl-extras also requires xscreensaver-gl-base IMO, xscreensaver should depend only on xscreensaver-base.
xscreensaver binary rpm is actually a virtual package to install 3 packages mentioned here (i.e. xscreensaver-{base,extras,gl-extras}) by just "yum install xscreensaver". If you want to use minimal function of xscreensaver, just install "xscreensaver-base". Note that xscreensaver binary rpm is introduced by me and I think only Fedora creates xscreensaver (virtual) package.