One of the common causes is that the installation file may have been corrupted during download. So, I think there is a chance that the update that you downloaded as corrupted during the download. What I would suggest is trying to download an update separate from the one available through the program's Check for Updates.
As a side note, it is not necessary to uninstall prior Qlikview before installing the latest version. However, the content in the newer version typically has all the content from the prior versions. So, there is not really a need to leave prior versions on the computer.