diff --git a/ec2-unikernel.cabal b/ec2-unikernel.cabal
--- a/ec2-unikernel.cabal
+++ b/ec2-unikernel.cabal
@@ -1,5 +1,5 @@
 name:                ec2-unikernel
-version:             0.9
+version:             0.9.1
 synopsis:            A handy tool for uploading unikernels to Amazon's EC2.
 description:         This tool uploads unikernels built with the HaLVM, Mirage,
                      or other tools to Amazon's cloud. The unikernel will then
diff --git a/src/CommandLine.hs b/src/CommandLine.hs
--- a/src/CommandLine.hs
+++ b/src/CommandLine.hs
@@ -16,7 +16,7 @@
                                                  dazrsAvailabilityZones,
                                                  dazZoneNames)
 import Network.AWS.EC2.Types(azZoneName)
-import Network.AWS.Types(Error(..), serviceCode)
+import Network.AWS.Types(ServiceError, Error(..))
 import Options
 import System.Console.GetOpt(ArgDescr(..), OptDescr(..), ArgOrder(..))
 import System.Console.GetOpt(getOpt, usageInfo)
@@ -46,7 +46,7 @@
   | length sk /= 40           = addError opts "Secret key doesn't look right."
   | any (not . isSecKeyCh) sk = addError opts "Secret key has weird characters."
   | otherwise                 = addOpt opts (set optAwsSecretKey (fromString sk))
- where isSecKeyCh c = isAlphaNum c || (c == '/')
+ where isSecKeyCh c = isAlphaNum c || (c == '/') || (c == '+')
 
 validateS3Bucket :: String -> OptOrErr -> OptOrErr
 validateS3Bucket b opts
@@ -137,15 +137,27 @@
          zoneRequest = set dazZoneNames [region] describeAvailabilityZones
      r <- catch ((runResourceT . runAWS e) (send zoneRequest))
             (\ (ServiceError se) ->
-               do putStr   "ERROR: Failed to connect with Amazon. "
-                  putStrLn "This is typically a problem with your keys."
-                  putStrLn ("       ("++show(view serviceCode se)++")")
-                  putStrLn (show se)
+               do printInitialServiceError se
                   exitWith (ExitFailure 1))
      let z = Just (view optS3Zone opts)
      unless (elemOf (dazrsAvailabilityZones . folded . azZoneName) z r) $
        fail' ["Invalid availability zone for region."]
      return (opts, e)
+
+printInitialServiceError :: ServiceError -> IO ()
+printInitialServiceError se =
+  do putStrLn "ERROR: Failed to get list of zones from Amazon. This typically"
+     putStrLn "is caused by one of two problems:"
+     putStrLn ""
+     putStrLn "  #1: There's something wrong with your keys. Check your"
+     putStrLn "      arguments, or make sure AWS_ACCESS_KEY and AWS_SECRET_KEY"
+     putStrLn "      are what you want them to be."
+     putStrLn "  #2: There's something wrong with your computer's clock. Run"
+     putStrLn "      whatever software you have to synchronize your clock, and"
+     putStrLn "      try again."
+     putStrLn ""
+     putStrLn "Just in case it's useful, here's the raw error:"
+     putStrLn (show se)
 
 adjustTargetName :: UTCTime -> Options -> Options
 adjustTargetName now opts
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -64,6 +64,7 @@
 import           System.IO.Temp(withSystemTempDirectory)
 import           System.Posix.Files(fileSize, getFileStatus)
 import           System.Process(callProcess)
+import           System.Timeout(timeout)
 
 main :: IO ()
 main =
@@ -116,7 +117,8 @@
 buildDisk :: Options -> IO FilePath
 buildDisk opts =
   withSystemTempDirectory "ec2-unikernel" $ \ path ->
-    do sizeb <- fileSize `fmap` getFileStatus (view optKernel opts)
+    do logm "DISK" ("Building disk.")
+       sizeb <- fileSize `fmap` getFileStatus (view optKernel opts)
        let sizem = ceiling (fromInteger (fromIntegral sizeb) / onemeg) + 1
        writeFile (path </> "menu.lst") (grubMenu opts)
        writeFile (path </> "guestfish.scr")
@@ -125,6 +127,7 @@
        callProcess "guestfish" ["-f", path </> "guestfish.scr"]
        let targetFile = unpack (toText (view optTargetKey opts))
        copyFile (path </> "disk.raw") targetFile
+       logm "DISK" ("Built disk " ++ targetFile)
        return targetFile
 
 grubMenu :: Options -> String
@@ -190,13 +193,15 @@
 
 uploadFile :: Options -> Env -> FilePath -> IO ()
 uploadFile opts e filename =
-  do rsp <- awsSend e (createMultipartUpload bucket key)
+  do logm "UPLOAD" "Creating upload."
+     rsp <- awsSend e (createMultipartUpload bucket key)
      case (view cmursUploadId rsp, view cmursResponseStatus rsp) of
        (Nothing, code) ->
          putStrLn ("ERROR: Upload initialization failed with code: "++show code)
        (Just upId, _) ->
          do bytes <- L.readFile filename
             sizeb <- fileSize `fmap` getFileStatus filename
+            logm "UPLOAD" "Starting upload."
             runUpload upId 0 (fromIntegral sizeb) bytes 1 []
  where
   bucket = view optS3Bucket  opts
@@ -225,7 +230,8 @@
         do let (chunkBS, rest) = L.splitAt amazonMinimimPartSizeInBytes bytes
                chunk           = Hashed (toHashed chunkBS)
                sentSize'       = sentSize + contentLength chunk
-           rsp <- awsSend e (uploadPart bucket key partNo upId chunk)
+               req             = uploadPart bucket key partNo upId chunk
+           rsp <- awsSend e req
            case (view uprsETag rsp, view uprsResponseStatus rsp) of
              (Nothing, code) ->
                do putStrLn ("ERROR: Upload failed with code: " ++ show code)
@@ -338,7 +344,15 @@
 logm category message = putStrLn (category ++ ": " ++ message)
 
 awsSend :: AWSRequest r => Env -> r -> IO (Rs r)
-awsSend e x = runResourceT (runAWS e (send x))
+awsSend env request = go 5 request
+ where
+  go :: AWSRequest r => Int -> r -> IO (Rs r)
+  go 0 _ = fail "Amazon request failed."
+  go x v =
+    do mrsp <- timeout (15 * 1000000) (runResourceT (runAWS env (send v)))
+       case mrsp of
+         Nothing  -> putStrLn "Retrying." >> go (x - 1) v
+         Just rsp -> return rsp
 
 show' :: Maybe Text -> String
 show' Nothing  = ""