--- README.rdoc
+++ README.rdoc
@@ -42,7 +42,7 @@ In a nutshell:
   data = Net::SCP::download!("remote.host.com", "username", "/remote/path")
 
   # use a persistent connection to transfer files
-  Net::SCP.start("remote.host.com", "username", :ssh => { :password => "password" }) do |scp|
+  Net::SCP.start("remote.host.com", "username", :password => "password") do |scp|
     # upload a file to a remote server
     scp.upload! "/local/path", "/remote/path"
 
--- lib/net/scp.rb
+++ lib/net/scp.rb
@@ -395,7 +395,7 @@ module Net
       def await_response_state(channel)
         return if channel[:buffer].available == 0
         c = channel[:buffer].read_byte
-        raise "#{c.chr}#{channel[:buffer].read}" if c != 0
+        raise Net::SCP::Error, "#{c.chr}#{channel[:buffer].read}" if c != 0
         channel[:next], channel[:state] = nil, channel[:next]
         send("#{channel[:state]}_state", channel)
       end
--- lib/net/scp/download.rb
+++ lib/net/scp/download.rb
@@ -129,7 +129,7 @@ module Net; class SCP
       channel[:local] = File.join(channel[:local], directive[:name])
 
       if File.exists?(channel[:local]) && !File.directory?(channel[:local])
-        raise "#{channel[:local]} already exists and is not a directory"
+        raise Net::SCP::Error, "#{channel[:local]} already exists and is not a directory"
       elsif !File.exists?(channel[:local])
         Dir.mkdir(channel[:local], directive[:mode] | 0700)
       end
@@ -162,4 +162,4 @@ module Net; class SCP
     end
   end
 
-end; end
\ No newline at end of file
+end; end
--- test/test_download.rb
+++ test/test_download.rb
@@ -158,6 +158,37 @@ class TestDownload < Net::SCP::TestCase
     assert_raises(Net::SCP::Error) { scp.download!("/path/to/remote") }
   end
 
+  def test_download_should_raise_error_if_gets_not_ok
+    prepare_file("/path/to/local.txt", "")
+
+    expect_scp_session "-f /path/to/remote.txt" do |channel|
+      channel.sends_ok
+      channel.gets_data "C0666 0 remote.txt\n"
+      channel.sends_ok
+      channel.gets_data "\1"
+    end
+
+    e = assert_raises(Net::SCP::Error) { scp.download!("/path/to/remote.txt", "/path/to/local.txt") }
+    assert_equal("\1", e.message)
+  end
+
+  def test_download_directory_should_raise_error_if_local_exists_and_is_not_directory
+    File.stubs(:exists?).with("/path/to/local").returns(true)
+    File.stubs(:exists?).with("/path/to/local/remote").returns(true)
+    File.stubs(:directory?).with("/path/to/local/remote").returns(false)
+
+    expect_scp_session "-f -r /path/to/remote" do |channel|
+      channel.sends_ok
+      channel.gets_data "D0755 0 remote\n"
+      channel.sends_ok
+      channel.gets_data "E\n"
+      channel.sends_ok
+    end
+    
+    e = assert_raises(Net::SCP::Error) { scp.download!("/path/to/remote", "/path/to/local", :recursive => true) }
+    assert_match(/exists and is not a directory/, e.message)
+  end
+
   def test_download_directory_should_create_directory_and_files_locally
     file = nil
     prepare_directory "/path/to/local" do |dir|