Downloaded the 15.1 Platform installer and ran it.  I received errors trying to install WPF (the only thing i was trying to install).  Here is the relevant portion of the log file it directed me to:

08:08:35: Log file initialized at: 4/8/2015 8:08:35 AM
08:08:35: Version number of the executable is: 15.1.20151.72
08:08:36: Checking proxy settings...
08:08:36: Proxy not found on the system!
08:08:41: Message to added
08:08:41: Message to added
08:08:41: Message to added
08:08:41: Message to added
08:08:41: Message to added
08:08:41: Message to added
08:08:41: serialnum matches expression:
08:08:41: Acceptable prefix found. Will validate the key
08:11:53: Message to added
08:11:53: Message to added
08:11:53: Message to added
08:11:53: Message to added
08:11:53: Message to added
08:11:53: Message to added
08:11:53: Setting up download of Infragistics_WPF_20151.msi
08:11:53: Beginning download of Infragistics_WPF_20151.msi
08:11:53: Error downloading Infragistics_WPF_20151.msi. Review the log file for details.
08:11:53: System.UriFormatException: Invalid URI: The URI is empty.
at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
at System.Uri..ctor(String uriString)
at Infragistics.Wrapper.Interface.Utilities.DownloadExecutionManager.downloadWork()
08:11:53: Setting up download of Infragistics_WPF_20151_Samples.msi
08:11:53: Beginning download of Infragistics_WPF_20151_Samples.msi
08:11:53: Error downloading Infragistics_WPF_20151_Samples.msi. Review the log file for details.
08:11:53: System.UriFormatException: Invalid URI: The URI is empty.
at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
at System.Uri..ctor(String uriString)
at Infragistics.Wrapper.Interface.Utilities.DownloadExecutionManager.downloadWork()
08:11:53: Setting up download of Infragistics_VersionUtility_20151.msi
08:11:53: Beginning download of Infragistics_VersionUtility_20151.msi
08:11:53: Error downloading Infragistics_VersionUtility_20151.msi. Review the log file for details.
08:11:53: System.UriFormatException: Invalid URI: The URI is empty.
at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
at System.Uri..ctor(String uriString)
at Infragistics.Wrapper.Interface.Utilities.DownloadExecutionManager.downloadWork()
08:11:53: Setting up download of Infragistics_VSExtension_20151.msi
08:11:53: Beginning download of Infragistics_VSExtension_20151.msi
08:11:53: Error downloading Infragistics_VSExtension_20151.msi. Review the log file for details.
08:11:53: System.UriFormatException: Invalid URI: The URI is empty.
at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
at System.Uri..ctor(String uriString)
at Infragistics.Wrapper.Interface.Utilities.DownloadExecutionManager.downloadWork()