diff --git a/core/src/net/sf/openrocket/logging/Error.java b/core/src/net/sf/openrocket/logging/Error.java
new file mode 100644
index 000000000..69ba76dd6
--- /dev/null
+++ b/core/src/net/sf/openrocket/logging/Error.java
@@ -0,0 +1,59 @@
+package net.sf.openrocket.logging;
+
+import net.sf.openrocket.l10n.Translator;
+import net.sf.openrocket.startup.Application;
+
+/**
+ * An error message wrapper.
+ */
+public abstract class Error extends Message {
+    private static final Translator trans = Application.getTranslator();
+
+    /**
+     * @return an Error with the specific text.
+     */
+    public static Error fromString(String text) {
+        return new Error.Other(text);
+    }
+
+
+    /////////////  Specific Error classes  /////////////
+
+
+    /**
+     * An unspecified error type.  This error type holds a <code>String</code>
+     * describing it.  Two errors of this type are considered equal if the strings
+     * are identical.
+     */
+    public static class Other extends Error {
+        private final String description;
+
+        public Other(String description) {
+            this.description = description;
+        }
+
+        @Override
+        public String toString() {
+            return description;
+        }
+
+        @Override
+        public boolean equals(Object other) {
+            if (!(other instanceof Other))
+                return false;
+
+            Other o = (Other) other;
+            return (o.description.equals(this.description));
+        }
+
+        @Override
+        public int hashCode() {
+            return description.hashCode();
+        }
+
+        @Override
+        public boolean replaceBy(Message other) {
+            return false;
+        }
+    }
+}
diff --git a/core/src/net/sf/openrocket/logging/ErrorSet.java b/core/src/net/sf/openrocket/logging/ErrorSet.java
new file mode 100644
index 000000000..76ea8977a
--- /dev/null
+++ b/core/src/net/sf/openrocket/logging/ErrorSet.java
@@ -0,0 +1,32 @@
+package net.sf.openrocket.logging;
+
+import net.sf.openrocket.util.BugException;
+
+public class ErrorSet extends MessageSet<Error> {
+    /**
+     * Add an <code>Error</code> with the specified text to the set.  The Error object
+     * is created using the {@link Error#fromString(String)} method.  If an error of the
+     * same type exists in the set, the error that is left in the set is defined by the
+     * method {@link Error#replaceBy(Message)}.
+     *
+     * @param s		the message text.
+     * @throws IllegalStateException	if this message set has been made immutable.
+     */
+    public boolean add(String s) {
+        mutable.check();
+        return add(Error.fromString(s));
+    }
+
+    @Override
+    public ErrorSet clone() {
+        try {
+            ErrorSet newSet = (ErrorSet) super.clone();
+            newSet.messages = this.messages.clone();
+            newSet.mutable = this.mutable.clone();
+            return newSet;
+
+        } catch (CloneNotSupportedException e) {
+            throw new BugException("CloneNotSupportedException occurred, report bug!", e);
+        }
+    }
+}