diff --git a/src/main/java/com/adobe/epubcheck/messages/MessageDictionary.java b/src/main/java/com/adobe/epubcheck/messages/MessageDictionary.java
index 0018eabd5..f5db165a0 100644
--- a/src/main/java/com/adobe/epubcheck/messages/MessageDictionary.java
+++ b/src/main/java/com/adobe/epubcheck/messages/MessageDictionary.java
@@ -92,6 +92,7 @@ static Map<MessageId, Severity> getDefaultSeverities()
       map.put(MessageId.CHK_005, Severity.ERROR);
       map.put(MessageId.CHK_006, Severity.ERROR);
       map.put(MessageId.CHK_007, Severity.ERROR);
+      map.put(MessageId.CHK_008, Severity.ERROR);
 
       // CSS
       map.put(MessageId.CSS_001, Severity.ERROR);
diff --git a/src/main/java/com/adobe/epubcheck/messages/MessageId.java b/src/main/java/com/adobe/epubcheck/messages/MessageId.java
index 81531aad1..e27adf341 100644
--- a/src/main/java/com/adobe/epubcheck/messages/MessageId.java
+++ b/src/main/java/com/adobe/epubcheck/messages/MessageId.java
@@ -55,6 +55,7 @@ public enum MessageId implements Comparable<MessageId>
   CHK_005("CHK-005"),
   CHK_006("CHK-006"),
   CHK_007("CHK-007"),
+  CHK_008("CHK-008"),
 
   // Messages associated with styles
   CSS_001("CSS-001"),
diff --git a/src/main/java/com/adobe/epubcheck/opf/OPFChecker.java b/src/main/java/com/adobe/epubcheck/opf/OPFChecker.java
index cb870af30..e710f8004 100755
--- a/src/main/java/com/adobe/epubcheck/opf/OPFChecker.java
+++ b/src/main/java/com/adobe/epubcheck/opf/OPFChecker.java
@@ -416,11 +416,15 @@ else if (item.isNav())
     }
     if (checkerFactory != null)
     {
-      // Create the content checker with an overridden validation context
-      ContentChecker checker = checkerFactory.newInstance(new ValidationContextBuilder(context)
-          .path(item.getPath()).mimetype(mimetype).properties(item.getProperties()).build());
-      // Validate
-      checker.runChecks();
+      try {
+        // Create the content checker with an overridden validation context
+        ContentChecker checker = checkerFactory.newInstance(new ValidationContextBuilder(context)
+            .path(item.getPath()).mimetype(mimetype).properties(item.getProperties()).build());
+        // Validate
+        checker.runChecks();
+      } catch (IllegalStateException e) {
+        report.message(MessageId.CHK_008, EPUBLocation.create(path), item.getPath());
+      }
     }
   }
 
diff --git a/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties b/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties
index fa192dd5d..a12c82590 100644
--- a/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties
+++ b/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties
@@ -32,6 +32,7 @@ CHK_004=The custom message contains too many parameters in message overrides fil
 CHK_005=The custom suggestion contains too many parameters in message overrides file '%1$s'.
 CHK_006=Unable to parse the custom format parameter in message overrides file '%1$s'.
 CHK_007=Error encountered while processing custom message file '%1$s': "%2$s".
+CHK_008=Error encountered while processing an item '%1$s'; skip other checkes for the item.
 
 #CSS
 CSS_001=The \'%1$s\' property must not be included in an EPUB Style Sheet.
diff --git a/src/test/java/com/adobe/epubcheck/api/Epub20CheckTest.java b/src/test/java/com/adobe/epubcheck/api/Epub20CheckTest.java
index ee3147964..369b0a038 100644
--- a/src/test/java/com/adobe/epubcheck/api/Epub20CheckTest.java
+++ b/src/test/java/com/adobe/epubcheck/api/Epub20CheckTest.java
@@ -272,4 +272,12 @@ public void testLinkedStylesheetCaseInsensitiveIssue316() {
 	  Collections.addAll(expectedErrors, MessageId.RSC_007);
     testValidateDocument("invalid/issue316.epub");
 	}
+
+  @Test
+  public void testValidateEPUB_issue21()
+  {
+    Collections.addAll(expectedErrors, MessageId.OPF_054, MessageId.OPF_050, MessageId.CHK_008);
+    Collections.addAll(expectedWarnings, MessageId.OPF_055);
+    testValidateDocument("/Issue21.epub");
+  }
 }