diff --git a/ext/passenger/native_support.c b/ext/passenger/native_support.c
index 52e0c29685..55fea2fa86 100644
--- a/ext/passenger/native_support.c
+++ b/ext/passenger/native_support.c
@@ -34,6 +34,12 @@
 #ifndef RARRAY_LEN
 	#define RARRAY_LEN(ary) RARRAY(ary)->len
 #endif
+#ifndef RSTRING_PTR
+	#define RSTRING_PTR(str) RSTRING(str)->ptr
+#endif
+#ifndef RSTRING_LEN
+	#define RSTRING_LEN(str) RSTRING(str)->len
+#endif
 
 static VALUE mPassenger;
 static VALUE mNativeSupport;
@@ -178,7 +184,8 @@ create_unix_socket(VALUE self, VALUE filename, VALUE backlog) {
 	char *filename_str;
 	long filename_length;
 	
-	filename_str = rb_str2cstr(filename, &filename_length);
+	filename_str = RSTRING_PTR(filename);
+	filename_length = RSTRING_LEN(filename);
 	
 	fd = socket(PF_UNIX, SOCK_STREAM, 0);
 	if (fd == -1) {
diff --git a/lib/passenger/rack/request_handler.rb b/lib/passenger/rack/request_handler.rb
index e718aea74d..abe742a918 100644
--- a/lib/passenger/rack/request_handler.rb
+++ b/lib/passenger/rack/request_handler.rb
@@ -66,13 +66,13 @@ def process_request(env, input, output)
 		begin
 			output.write("Status: #{status}#{CRLF}")
 			headers[X_POWERED_BY] = PASSENGER_HEADER
-			headers.each do |k, vs|
-				vs.each do |v|
-					output.write("#{k}: #{v}#{CRLF}")
-				end
+			headers.each_pair do |k, v|
+				output.write("#{k}: #{v}#{CRLF}")
 			end
 			output.write(CRLF)
-			if body
+			if body.is_a?(String)
+				output.write(body)
+			elsif body
 				body.each do |s|
 					output.write(s)
 				end
diff --git a/lib/passenger/utils.rb b/lib/passenger/utils.rb
index 01514037ee..b9deb5948a 100644
--- a/lib/passenger/utils.rb
+++ b/lib/passenger/utils.rb
@@ -18,7 +18,7 @@
 
 require 'rubygems'
 require 'thread'
-if RUBY_PLATFORM != "java" && RUBY_VERSION < "1.8.7"
+if (!defined?(RUBY_ENGINE) || RUBY_ENGINE == "ruby") && RUBY_VERSION < "1.8.7"
 	require 'fastthread'
 end
 require 'pathname'
@@ -26,7 +26,7 @@
 require 'fcntl'
 require 'tempfile'
 require 'passenger/exceptions'
-if RUBY_PLATFORM != "java"
+if !defined?(RUBY_ENGINE) || RUBY_ENGINE == "ruby"
 	require 'passenger/native_support'
 end