In some cases the DataPA addin is not available. If the VSTo Addin File is run from the O/S the install fails with errors like 

System.Deployment.Application.DeploymentDownloadException: Downloading file:///C:/Program Files (x86)/DataPA/Excel/DataPA OpenAnalytics Excel Addin.dll.config did not succeed. ---> System.Net.WebException: Could not find file 'C:\Program Files (x86)\DataPA\Excel\DataPA OpenAnalytics Excel Addin.dll.config'. ---> System.Net.WebException: Could not find file 'C:\Program Files (x86)\DataPA\Excel\DataPA OpenAnalytics Excel Addin.dll.config'. ---> System.IO.FileNotFoundException: Could not find file 'C:\Program Files (x86)\DataPA\Excel\DataPA OpenAnalytics Excel Addin.dll.config'.

at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)

at System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy, Boolean useLongPath, Boolean checkHost)

at System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy)

To resole this issue, Remove DataPA and ReInstall