I have seen an issue where JuniperSetupClient.exe is flagged as missing, offered for download, you install it, and then it goes right back to being flagged as missing again. In my case, it was Firefox and an outdated version of Java. Firefox will disable old Java plugins, because they are so very unsafe. I resolved this by installing current Java (7u25 right now), and uninstalling all old copies of Java.
To see whether it's a browser issue, try it in IE. You can also try from a "fresh" user profile, to see whether it's profile-related, and you can try and uninstall everything Juniper (Network Connect, Host Checker, Pulse are the usual suspects) to see whether this is related to a corrupted install on the client machine.
Note that Chrome isn't supported by IVEOS. IE, Firefox and Safari are. The safe bet is to try IE first, always.