Index: src/protocol/http/org/apache/jmeter/protocol/http/proxy/HttpRequestHdr.java
===================================================================
--- src/protocol/http/org/apache/jmeter/protocol/http/proxy/HttpRequestHdr.java	(revision 1509948)
+++ src/protocol/http/org/apache/jmeter/protocol/http/proxy/HttpRequestHdr.java	(working copy)
@@ -21,7 +21,9 @@
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.net.URI;
 import java.net.URL;
+import java.net.URLDecoder;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.StringTokenizer;
@@ -167,9 +169,31 @@
         if (url.startsWith("/")) {
             url = HTTPS + "://" + paramHttps + url; // $NON-NLS-1$
         }
+        try {
+            URI testCleanUri = new URI(url);
+        } catch (Exception e) {
+            log.info("Url contains unsafe characters");
+            try {
+                url = escapeIllegalURLCharacters(url);
+            } catch (Exception e1) {
+                log.error("Error sanitzing URL:"+url);
+            }
+        }
         log.debug("First Line: " + url);
     }
 
+    /**
+     * @param url
+     * @return
+     * @throws Exception
+     */
+    public static String escapeIllegalURLCharacters(String url) throws Exception{
+        String decodeUrl = URLDecoder.decode(url,"UTF-8");
+        URL urlString = new URL(decodeUrl);
+        URI uri = new URI(urlString.getProtocol(), urlString.getUserInfo(), urlString.getHost(), urlString.getPort(), urlString.getPath(), urlString.getQuery(), urlString.getRef());
+        return uri.toString();
+    }
+    
     /*
      * Split line into name/value pairs and store in headers if relevant
      * If name = "content-length", then return value as int, else return 0