The latest cloudera manager installer is broken, it points to the wrong repository. It seems this was immediately fixed in version 5.5.0.1, however the download link shown on the Cloudera Manager download page actually points to the 5.5.0 version. The directory containing cm5 installers hints at what the problem might be: 5.5.0.1 is sorted before 5.5.0.
A small side note: there does not seem to be a 5.5.x label for this forum yet.