I ended up getting past this after completely removing everything and reinstalling. That seemed to fix the specific problem here. Now though I'm getting 500 errors any time I try to use Bing maps, but it works fine when using SRTM.
System.Net.WebException: The remote server returned an error: (500) DEM server did not return tile..
at System.Net.HttpWebRequest.CheckFinalStatus (System.Net.WebAsyncResult result) [0x00000] in <filename unknown>:0
at System.Net.HttpWebRequest.SetResponseData (System.Net.WebConnectionData data) [0x00000] in <filename unknown>:0
UnityEngine.Debug:Log(Object)
RealWorldTerrainDownloaderItem:OnDownloadDataComplete(Object, DownloadDataCompletedEventArgs) (at Assets/Infinity Code/Real World Terrain/Scripts/Editor/RealWorldTerrainDownloader.cs:292)
System.Net.WebClient:<DownloadDataAsync>m__D(Object)
And if it is not a 500 error it is a request timeout
System.Net.WebException: The request timed out
at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0
at System.Net.HttpWebRequest.GetResponse () [0x00000] in <filename unknown>:0
at System.Net.WebClient.GetWebResponse (System.Net.WebRequest request) [0x00000] in <filename unknown>:0
at System.Net.WebClient.DownloadDataCore (System.Uri address, System.Object userToken) [0x00000] in <filename unknown>:0
UnityEngine.Debug:Log(Object)
RealWorldTerrainDownloaderItem:OnDownloadDataComplete(Object, DownloadDataCompletedEventArgs) (at Assets/Infinity Code/Real World Terrain/Scripts/Editor/RealWorldTerrainDownloader.cs:292)
System.Net.WebClient:<DownloadDataAsync>m__D(Object)