diff --git a/Distribution/Client/Configure.hs b/Distribution/Client/Configure.hs
--- a/Distribution/Client/Configure.hs
+++ b/Distribution/Client/Configure.hs
@@ -48,7 +48,7 @@
 import Distribution.Version
          ( anyVersion, thisVersion )
 import Distribution.Simple.Utils as Utils
-         ( notice, debug, die )
+         ( notice, info, debug, die )
 import Distribution.System
          ( Platform )
 import Distribution.Verbosity as Verbosity
@@ -95,7 +95,10 @@
   maybePlan <- foldProgress logMsg (return . Left) (return . Right)
                             progress
   case maybePlan of
-    Left message -> die message
+    Left message -> do
+      info verbosity message
+      setupWrapper verbosity (setupScriptOptions installedPkgIndex) Nothing
+        configureCommand (const configFlags) extraArgs
 
     Right installPlan -> case InstallPlan.ready installPlan of
       [pkg@(ReadyPackage (SourcePackage _ _ (LocalUnpackedPackage _) _) _ _ _)] ->
diff --git a/Distribution/Client/HttpUtils.hs b/Distribution/Client/HttpUtils.hs
--- a/Distribution/Client/HttpUtils.hs
+++ b/Distribution/Client/HttpUtils.hs
@@ -31,6 +31,8 @@
 import Distribution.Simple.Utils
          ( die, info, warn, debug, notice
          , copyFileVerbose, writeFileAtomic )
+import Distribution.System
+         ( buildOS, buildArch )
 import Distribution.Text
          ( display )
 import Data.Char ( isSpace )
@@ -67,7 +69,9 @@
                             , rqMethod  = GET
                             , rqHeaders = Header HdrUserAgent userAgent : ifNoneMatchHdr
                             , rqBody    = ByteString.empty }
-  where userAgent = "cabal-install/" ++ display Paths_cabal_install.version
+  where userAgent = concat [ "cabal-install/", display Paths_cabal_install.version
+                           , " (", display buildOS, "; ", display buildArch, ")"
+                           ]
         ifNoneMatchHdr = maybe [] (\t -> [Header HdrIfNoneMatch t]) etag
 
 -- |Carry out a GET request, using the local proxy settings
diff --git a/Main.hs b/Main.hs
--- a/Main.hs
+++ b/Main.hs
@@ -140,7 +140,7 @@
 
 import System.Environment       (getArgs, getProgName)
 import System.Exit              (exitFailure)
-import System.FilePath          (splitExtension, takeExtension)
+import System.FilePath          (splitExtension, takeExtension, searchPathSeparator)
 import System.IO                (BufferMode(LineBuffering),
                                  hSetBuffering, stdout)
 import System.Directory         (doesFileExist, getCurrentDirectory)
@@ -1046,7 +1046,8 @@
                 exitFailure
             Just ghcProg ->  do
                 g <- ghcGlobalPackageDB verbosity ghcProg
-                getEffectiveEnvironment [("GHC_PACKAGE_PATH", Just $ s ++ ":" ++ g)]
+                getEffectiveEnvironment
+                  [("GHC_PACKAGE_PATH", Just $ s ++ [searchPathSeparator] ++ g)]
 
 -- | See 'Distribution.Client.Install.withWin32SelfUpgrade' for details.
 --
diff --git a/cabal-install.cabal b/cabal-install.cabal
--- a/cabal-install.cabal
+++ b/cabal-install.cabal
@@ -1,5 +1,5 @@
 Name:               cabal-install
-Version:            1.20.0.0
+Version:            1.20.0.1
 Synopsis:           The command-line interface for Cabal and Hackage.
 Description:
     The \'cabal\' command-line program simplifies the process of managing