I had this problem.  It turns out the download wasn't completing.  For some reason, my download kept pausing and resuming and sometimes never completing.  Download it again and try.
My Wyse Device Manager install gives an error when i start the setup. Error : The WyseInstall.dll could not be loaded into memory. Please restart setup.exe or call Wyse Technology Support for assistance.  Tried the installation on several machines and always the same error. Any help would be welcome !
Wyse Device Manager 5.7(.1) won't install