diff --git a/include/YapError.h b/include/YapError.h
new file mode 100644
index 000000000..be84c3d4c
--- /dev/null
+++ b/include/YapError.h
@@ -0,0 +1,120 @@
+/*************************************************************************
+*									 *
+*	 YAP Prolog 	%W% %G% 					 *
+*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
+*									 *
+* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
+*									 *
+**************************************************************************
+*									 *
+* File:		YapError.h   						 *
+* mods:									 *
+* comments:	error header file for YAP				 *
+* version:      $Id: Yap.h,v 1.38 2008-06-18 10:02:27 vsc Exp $	 *
+*************************************************************************/
+
+/* Types of Errors */
+typedef enum
+{
+  YAP_NO_ERROR,
+  FATAL_ERROR,
+  INTERNAL_ERROR,
+  INTERNAL_COMPILER_ERROR,
+  PURE_ABORT,
+  CALL_COUNTER_UNDERFLOW,
+  /* ISO_ERRORS */
+  CONSISTENCY_ERROR,
+  DOMAIN_ERROR_ARRAY_OVERFLOW,
+  DOMAIN_ERROR_ARRAY_TYPE,
+  DOMAIN_ERROR_IO_MODE,
+  DOMAIN_ERROR_MUTABLE,
+  DOMAIN_ERROR_NON_EMPTY_LIST,
+  DOMAIN_ERROR_NOT_LESS_THAN_ZERO,
+  DOMAIN_ERROR_NOT_NL,
+  DOMAIN_ERROR_NOT_ZERO,
+  DOMAIN_ERROR_OUT_OF_RANGE,
+  DOMAIN_ERROR_OPERATOR_PRIORITY,
+  DOMAIN_ERROR_OPERATOR_SPECIFIER,
+  DOMAIN_ERROR_RADIX,
+  DOMAIN_ERROR_SHIFT_COUNT_OVERFLOW,
+  DOMAIN_ERROR_SOURCE_SINK,
+  DOMAIN_ERROR_STREAM,
+  DOMAIN_ERROR_STREAM_ENCODING,
+  DOMAIN_ERROR_STREAM_OR_ALIAS,
+  DOMAIN_ERROR_STREAM_POSITION,
+  DOMAIN_ERROR_TIMEOUT_SPEC,
+  DOMAIN_ERROR_SYNTAX_ERROR_HANDLER,
+  EVALUATION_ERROR_FLOAT_OVERFLOW,
+  EVALUATION_ERROR_FLOAT_UNDERFLOW,
+  EVALUATION_ERROR_INT_OVERFLOW,
+  EVALUATION_ERROR_UNDEFINED,
+  EVALUATION_ERROR_UNDERFLOW,
+  EVALUATION_ERROR_ZERO_DIVISOR,
+  EXISTENCE_ERROR_ARRAY,
+  EXISTENCE_ERROR_KEY,
+  EXISTENCE_ERROR_SOURCE_SINK,
+  EXISTENCE_ERROR_STREAM,
+  EXISTENCE_ERROR_VARIABLE,
+  INSTANTIATION_ERROR,
+  INTERRUPT_ERROR,
+  OPERATING_SYSTEM_ERROR,
+  OUT_OF_HEAP_ERROR,
+  OUT_OF_STACK_ERROR,
+  OUT_OF_TRAIL_ERROR,
+  OUT_OF_ATTVARS_ERROR,
+  OUT_OF_AUXSPACE_ERROR,
+  PERMISSION_ERROR_ACCESS_PRIVATE_PROCEDURE,
+  PERMISSION_ERROR_NEW_ALIAS_FOR_STREAM,
+  PERMISSION_ERROR_CREATE_ARRAY,
+  PERMISSION_ERROR_CREATE_OPERATOR,
+  PERMISSION_ERROR_INPUT_BINARY_STREAM,
+  PERMISSION_ERROR_INPUT_PAST_END_OF_STREAM,
+  PERMISSION_ERROR_INPUT_STREAM,
+  PERMISSION_ERROR_INPUT_TEXT_STREAM,
+  PERMISSION_ERROR_MODIFY_STATIC_PROCEDURE,
+  PERMISSION_ERROR_OPEN_SOURCE_SINK,
+  PERMISSION_ERROR_OUTPUT_BINARY_STREAM,
+  PERMISSION_ERROR_OUTPUT_STREAM,
+  PERMISSION_ERROR_OUTPUT_TEXT_STREAM,
+  PERMISSION_ERROR_RESIZE_ARRAY,
+  PERMISSION_ERROR_REPOSITION_STREAM,
+  PRED_ENTRY_COUNTER_UNDERFLOW,
+  REPRESENTATION_ERROR_CHARACTER,
+  REPRESENTATION_ERROR_CHARACTER_CODE,
+  REPRESENTATION_ERROR_MAX_ARITY,
+  REPRESENTATION_ERROR_VARIABLE,
+  RESOURCE_ERROR_HUGE_INT,
+  RESOURCE_ERROR_MAX_STREAMS,
+  RESOURCE_ERROR_MAX_THREADS,
+  RESOURCE_ERROR_MEMORY,
+  RESOURCE_ERROR_STACK,
+  RETRY_COUNTER_UNDERFLOW,
+  SAVED_STATE_ERROR,
+  SYNTAX_ERROR,
+  SYSTEM_ERROR,
+  TYPE_ERROR_ARRAY,
+  TYPE_ERROR_ATOM,
+  TYPE_ERROR_ATOMIC,
+  TYPE_ERROR_BYTE,
+  TYPE_ERROR_CALLABLE,
+  TYPE_ERROR_CHAR,
+  TYPE_ERROR_CHARACTER,
+  TYPE_ERROR_COMPOUND,
+  TYPE_ERROR_DBREF,
+  TYPE_ERROR_DBTERM,
+  TYPE_ERROR_EVALUABLE,
+  TYPE_ERROR_FLOAT,
+  TYPE_ERROR_INTEGER,
+  TYPE_ERROR_KEY,
+  TYPE_ERROR_LIST,
+  TYPE_ERROR_NUMBER,
+  TYPE_ERROR_PREDICATE_INDICATOR,
+  TYPE_ERROR_PTR,
+  TYPE_ERROR_STRING,
+  TYPE_ERROR_UBYTE,
+  TYPE_ERROR_UCHAR,
+  TYPE_ERROR_VARIABLE,
+  UNKNOWN_ERROR
+} yap_error_number;
+
+