diff --git a/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunk.java b/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunk.java
index 5c77eb7..ca43dfc 100644
--- a/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunk.java
+++ b/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunk.java
@@ -51,6 +51,6 @@ public boolean isEarlyTerminated() {
 	}
 	
 	public String toString() {
-		return "DeafultIcapChunk: [isPreviewChunk=" + preview + "] [wasEarlyTerminated=" + earlyTerminated + "] [data=" + getContent().readableBytes() + "]";
+		return "DefaultIcapChunk: [isPreviewChunk=" + preview + "] [wasEarlyTerminated=" + earlyTerminated + "] [data=" + getContent().readableBytes() + "]";
 	}
 }
diff --git a/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunkTrailer.java b/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunkTrailer.java
index 0b0223f..8b0bf84 100644
--- a/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunkTrailer.java
+++ b/src/main/java/ch/mimo/netty/handler/codec/icap/DefaultIcapChunkTrailer.java
@@ -63,6 +63,6 @@ public boolean isEarlyTerminated() {
 	}
 	
 	public String toString() {
-		return "DeafultIcapChunkTrailer: [isPreviewChunk=" + preview + "] [wasEarlyTerminated=" + earlyTerminated + "]";
+		return "DefaultIcapChunkTrailer: [isPreviewChunk=" + preview + "] [wasEarlyTerminated=" + earlyTerminated + "]";
 	}
 }
diff --git a/src/main/java/ch/mimo/netty/handler/codec/icap/IcapChunkAggregator.java b/src/main/java/ch/mimo/netty/handler/codec/icap/IcapChunkAggregator.java
index fa64fb5..dbaed2c 100644
--- a/src/main/java/ch/mimo/netty/handler/codec/icap/IcapChunkAggregator.java
+++ b/src/main/java/ch/mimo/netty/handler/codec/icap/IcapChunkAggregator.java
@@ -116,6 +116,10 @@ public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Ex
     			ctx.sendUpstream(e);
     		} else {
     			IcapChunkTrailer trailer = (IcapChunkTrailer)msg;
+    			if (trailer.isEarlyTerminated()) {
+    				LOG.debug("chunk trailer is early terminated, removing PREVIEW header");
+    				message.getIcapMessage().removeHeader(IcapHeaders.Names.PREVIEW);
+    			}
     			if(trailer.getHeaderNames().size() > 0) {		
     				for(String name : trailer.getHeaderNames()) {
     					message.addHeader(name,trailer.getHeader(name));
diff --git a/src/main/java/ch/mimo/netty/handler/codec/icap/IcapHeaders.java b/src/main/java/ch/mimo/netty/handler/codec/icap/IcapHeaders.java
index 01a145f..399521b 100644
--- a/src/main/java/ch/mimo/netty/handler/codec/icap/IcapHeaders.java
+++ b/src/main/java/ch/mimo/netty/handler/codec/icap/IcapHeaders.java
@@ -334,6 +334,9 @@ public void removeHeader(String name) {
 					after.before = before;
 					entry = after;
 				} else {
+					if (head == entry) {
+						head = entry.before;
+					}
 					entry = null;
 				}
 			} else {
diff --git a/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapHeaderState.java b/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapHeaderState.java
index 45d7698..7be84b1 100644
--- a/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapHeaderState.java
+++ b/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapHeaderState.java
@@ -63,7 +63,7 @@ public StateReturnValue execute(ChannelBuffer buffer, IcapMessageDecoder icapMes
 		}
 		if(isOptionsRequest) {
 			return StateReturnValue.createRelevantResult(icapMessageDecoder.message);
-		} else if(encapsulated != null && !encapsulated.containsEntry(IcapMessageElementEnum.REQHDR) & !encapsulated.containsEntry(IcapMessageElementEnum.RESHDR)) {
+		} else if(encapsulated != null && !encapsulated.containsEntry(IcapMessageElementEnum.REQHDR) && !encapsulated.containsEntry(IcapMessageElementEnum.RESHDR)) {
 			return StateReturnValue.createRelevantResult(icapMessageDecoder.message);
 		}
 		return StateReturnValue.createIrrelevantResult();
@@ -119,7 +119,7 @@ private void validateMandatoryMessageHeaders(IcapMessage message) {
 	private void handleEncapsulationHeaderVolatility(IcapMessage message) {
 		// Pseudo code
 		// IF Encapsulated header is missing
-			// IF OPTIONS request OR 100 Continue response OR 204 No Content response
+			// IF OPTIONS request OR 100 Continue response OR 204 No Content response OR is a server error
 				// THEN inject synthetic null-body Encapsulated header.
 		boolean requiresSynthecticEncapsulationHeader = false;
 		if(!message.containsHeader(IcapHeaders.Names.ENCAPSULATED)) {
@@ -128,7 +128,9 @@ private void handleEncapsulationHeaderVolatility(IcapMessage message) {
 			} else if(message instanceof IcapResponse) {
 				IcapResponse response = (IcapResponse)message;
 				IcapResponseStatus status = response.getStatus();
-				if(status.equals(IcapResponseStatus.CONTINUE) | status.equals(IcapResponseStatus.NO_CONTENT)) {
+				if(status.equals(IcapResponseStatus.CONTINUE) ||
+					status.equals(IcapResponseStatus.NO_CONTENT) ||
+					(status.getCode() >= 500)) {
 					requiresSynthecticEncapsulationHeader = true;
 				}
 			}
diff --git a/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapInitialState.java b/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapInitialState.java
index 321dca4..a164035 100644
--- a/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapInitialState.java
+++ b/src/main/java/ch/mimo/netty/handler/codec/icap/ReadIcapInitialState.java
@@ -39,7 +39,14 @@ public void onEntry(ChannelBuffer buffer, IcapMessageDecoder icapMessageDecoder)
 	@Override
 	public StateReturnValue execute(ChannelBuffer buffer, IcapMessageDecoder icapMessageDecoder) throws DecodingException {
 		String[] initialLine = IcapDecoderUtil.splitInitialLine(IcapDecoderUtil.readLine(buffer,icapMessageDecoder.maxInitialLineLength));
-		icapMessageDecoder.message = icapMessageDecoder.createMessage(initialLine);
+		if (initialLine.length >= 3) {
+			try {
+				icapMessageDecoder.message = icapMessageDecoder.createMessage(initialLine);
+			}
+			catch (IllegalArgumentException e) {
+				icapMessageDecoder.message = null;
+			}
+		}
 		return StateReturnValue.createIrrelevantResult();
 	}
 
diff --git a/src/test/java/ch/mimo/netty/handler/codec/icap/IcapHeaderTest.java b/src/test/java/ch/mimo/netty/handler/codec/icap/IcapHeaderTest.java
index 582a1c2..701c06f 100644
--- a/src/test/java/ch/mimo/netty/handler/codec/icap/IcapHeaderTest.java
+++ b/src/test/java/ch/mimo/netty/handler/codec/icap/IcapHeaderTest.java
@@ -330,4 +330,17 @@ public void getDateHeader() {
 		Date returnedDate = headers.getDateHeader(IcapHeaders.Names.DATE);
 		assertNotNull("The returned date was null",returnedDate);
 	}
+
+	@Test
+	public void removeAddHead() {
+		IcapHeaders headers = new IcapHeaders();
+		headers.addHeader("fuz", "buz");
+		headers.addHeader("foo", "bar");
+		assertTrue("Header 'FOO' should exist (1)", headers.containsHeader("foo"));
+		assertEquals("Header 'FOO' should be 'bar'", "bar", headers.getHeader("foo"));
+		headers.removeHeader("foo");
+		headers.addHeader("foo", "baz");
+		assertTrue("Header 'FOO' should exist (2)", headers.containsHeader("foo"));
+		assertEquals("Header 'FOO' should be 'baz'", "baz", headers.getHeader("foo"));
+	}
 }