Fix error handling in Install-IronPython.ps1

Author: BCSharp

Src/Scripts/Install-IronPython.ps1

@@ -64,12 +64,13 @@ if (-not $ZipFile) {
         # Script run from within a checked out code base
         # Locate the zip archive in the standard location of the package target
         $projectRoot = $PSScriptRoot | Split-Path | Split-Path
-        $ZipFile = @(Resolve-Path (Join-Path $projectRoot "Package/Release/Packages/IronPython-*/IronPython.3.*.zip"))
-        if ($ZipFile.Count -gt 1) {
-            Write-Error "Ambiguous implicit project zip file: $ZipFile"
-        } elseif ($ZipFile.Count -lt 1) {
+        $zipFiles = @(Resolve-Path (Join-Path $projectRoot "Package/Release/Packages/IronPython-*/IronPython.3.*.zip"))
+        if ($zipFiles.Count -gt 1) {
+            Write-Error (@("Ambiguous implicit project zip files:") + $zipFiles -join "`n")
+        } elseif ($zipFiles.Count -lt 1) {
             Write-Error "Missing zip file. Have you run './make package'?"
         }
+        $ZipFile = $zipFiles
     } else {
         Write-Error "Cannot locate implicit zip file. Provide path to the zip file using '-ZipFile <path>'."
     }