@@ -994,8 +994,34 @@
 
 	string = [[OFString alloc] initWithFormat:
 	    @"The requested action cannot be performed because the thread of "
 	    @"class %s was canceled!", [class_ className]];
 
+	return string;
+}
+@end
+
+@implementation OFMutexLockFailedException
+- (OFString*)string
+{
+	if (string != nil)
+		return string;
+
+	string = [[OFString alloc] initWithFormat:
+	    @"A mutex could not be locked in class %s", [class_ className]];
+
+	return string;
+}
+@end
+
+@implementation OFMutexUnlockFailedException
+- (OFString*)string
+{
+	if (string != nil)
+		return string;
+
+	string = [[OFString alloc] initWithFormat:
+	    @"A mutex could not be unlocked in class %s", [class_ className]];
+
 	return string;
 }
 @end