diff --git a/src/cpp/ripple/RPCErr.cpp b/src/cpp/ripple/RPCErr.cpp
new file mode 100644
index 000000000..cc0e6ba17
--- /dev/null
+++ b/src/cpp/ripple/RPCErr.cpp
@@ -0,0 +1,81 @@
+
+#include "Log.h"
+
+#include "RPCErr.h"
+#include "utils.h"
+
+#include "../json/writer.h"
+
+SETUP_LOG();
+
+Json::Value rpcError(int iError, Json::Value jvResult)
+{
+	static struct {
+		int			iError;
+		const char*	pToken;
+		const char*	pMessage;
+	} errorInfoA[] = {
+		{ rpcACT_EXISTS,			"actExists",		"Account already exists."								},
+		{ rpcACT_MALFORMED,			"actMalformed",		"Account malformed."									},
+		{ rpcACT_NOT_FOUND,			"actNotFound",		"Account not found."									},
+		{ rpcBAD_SEED,				"badSeed",			"Disallowed seed."										},
+		{ rpcBAD_SYNTAX,			"badSyntax",		"Syntax error."											},
+		{ rpcDST_ACT_MALFORMED,		"dstActMalformed",	"Destination account is malformed."						},
+		{ rpcDST_ACT_MISSING,		"dstActMissing",	"Destination account does not exists."					},
+		{ rpcDST_AMT_MALFORMED,		"dstAmtMalformed",	"Destination amount/currency/issuer is malformed."		},
+		{ rpcFAIL_GEN_DECRPYT,		"failGenDecrypt",	"Failed to decrypt generator."							},
+		{ rpcGETS_ACT_MALFORMED,	"getsActMalformed",	"Gets account malformed."								},
+		{ rpcGETS_AMT_MALFORMED,	"getsAmtMalformed",	"Gets amount malformed."								},
+		{ rpcHOST_IP_MALFORMED,		"hostIpMalformed",	"Host IP is malformed."									},
+		{ rpcINSUF_FUNDS,			"insufFunds",		"Insufficient funds."									},
+		{ rpcINTERNAL,				"internal",			"Internal error."										},
+		{ rpcINVALID_PARAMS,		"invalidParams",	"Invalid parameters."									},
+		{ rpcLGR_IDXS_INVALID,		"lgrIdxsInvalid",	"Ledger indexes invalid."								},
+		{ rpcLGR_IDX_MALFORMED,		"lgrIdxMalformed",	"Ledger index malformed."								},
+		{ rpcLGR_NOT_FOUND,			"lgrNotFound",		"Ledger not found."										},
+		{ rpcNICKNAME_MALFORMED,	"nicknameMalformed","Nickname is malformed."								},
+		{ rpcNICKNAME_MISSING,		"nicknameMissing",	"Nickname does not exist."								},
+		{ rpcNICKNAME_PERM,			"nicknamePerm",		"Account does not control nickname."					},
+		{ rpcNOT_IMPL,				"notImpl",			"Not implemented."										},
+		{ rpcNO_ACCOUNT,			"noAccount",		"No such account."										},
+		{ rpcNO_CLOSED,				"noClosed",			"Closed ledger is unavailable."							},
+		{ rpcNO_CURRENT,			"noCurrent",		"Current ledger is unavailable."						},
+		{ rpcNO_EVENTS,				"noEvents",			"Current transport does not support events."			},
+		{ rpcNO_GEN_DECRPYT,		"noGenDectypt",		"Password failed to decrypt master public generator."	},
+		{ rpcNO_NETWORK,			"noNetwork",		"Network not available."								},
+		{ rpcNO_PATH,				"noPath",			"Unable to find a ripple path."							},
+		{ rpcNO_PERMISSION,			"noPermission",		"You don't have permission for this command."			},
+		{ rpcNOT_STANDALONE,		"notStandAlone",	"Operation valid in debug mode only."					},
+		{ rpcPASSWD_CHANGED,		"passwdChanged",	"Wrong key, password changed."							},
+		{ rpcPAYS_ACT_MALFORMED,	"paysActMalformed",	"Pays account malformed."								},
+		{ rpcPAYS_AMT_MALFORMED,	"paysAmtMalformed",	"Pays amount malformed."								},
+		{ rpcPORT_MALFORMED,		"portMalformed",	"Port is malformed."									},
+		{ rpcPUBLIC_MALFORMED,		"publicMalformed",	"Public key is malformed."								},
+		{ rpcQUALITY_MALFORMED,		"qualityMalformed",	"Quality malformed."									},
+		{ rpcSRC_ACT_MALFORMED,		"srcActMalformed",	"Source account is malformed."							},
+		{ rpcSRC_ACT_MISSING,		"srcActMissing",	"Source account does not exist."						},
+		{ rpcSRC_AMT_MALFORMED,		"srcAmtMalformed",	"Source amount/currency/issuer is malformed."			},
+		{ rpcSRC_UNCLAIMED,			"srcUnclaimed",		"Source account is not claimed."						},
+		{ rpcSUCCESS,				"success",			"Success."												},
+		{ rpcTXN_NOT_FOUND,			"txnNotFound",		"Transaction not found."								},
+		{ rpcUNKNOWN_COMMAND,		"unknownCmd",		"Unknown command."										},
+		{ rpcWRONG_SEED,			"wrongSeed",		"The regular key does not point as the master key."		},
+	};
+
+	int		i;
+
+	for (i=NUMBER(errorInfoA); i-- && errorInfoA[i].iError != iError;)
+		;
+
+	jvResult["error"]			= i >= 0 ? errorInfoA[i].pToken : lexical_cast_i(iError);
+	jvResult["error_message"]	= i >= 0 ? errorInfoA[i].pMessage : lexical_cast_i(iError);
+	jvResult["error_code"]		= iError;
+
+	if (i >= 0)
+		cLog(lsDEBUG) << "rpcError: "
+			<< errorInfoA[i].pToken << ": " << errorInfoA[i].pMessage << std::endl;
+
+	return jvResult;
+}
+
+// vim:ts=4
diff --git a/src/cpp/ripple/RPCErr.h b/src/cpp/ripple/RPCErr.h
new file mode 100644
index 000000000..d22b66b02
--- /dev/null
+++ b/src/cpp/ripple/RPCErr.h
@@ -0,0 +1,71 @@
+#ifndef __RPCERR__
+#define __RPCERR__
+
+#include "../json/value.h"
+
+enum {
+	rpcSUCCESS,
+
+	rpcBAD_SYNTAX,	// Must be 1 to print usage to command line.
+
+	// Misc failure
+	rpcLOAD_FAILED,
+	rpcNO_PERMISSION,
+	rpcNO_EVENTS,
+	rpcNOT_STANDALONE,
+
+	// Networking
+	rpcNO_CLOSED,
+	rpcNO_CURRENT,
+	rpcNO_NETWORK,
+
+	// Ledger state
+	rpcACT_EXISTS,
+	rpcACT_NOT_FOUND,
+	rpcINSUF_FUNDS,
+	rpcLGR_NOT_FOUND,
+	rpcNICKNAME_MISSING,
+	rpcNO_ACCOUNT,
+	rpcNO_PATH,
+	rpcPASSWD_CHANGED,
+	rpcSRC_MISSING,
+	rpcSRC_UNCLAIMED,
+	rpcTXN_NOT_FOUND,
+	rpcWRONG_SEED,
+
+	// Malformed command
+	rpcINVALID_PARAMS,
+	rpcUNKNOWN_COMMAND,
+
+	// Bad parameter
+	rpcACT_MALFORMED,
+	rpcQUALITY_MALFORMED,
+	rpcBAD_SEED,
+	rpcDST_ACT_MALFORMED,
+	rpcDST_ACT_MISSING,
+	rpcDST_AMT_MALFORMED,
+	rpcGETS_ACT_MALFORMED,
+	rpcGETS_AMT_MALFORMED,
+	rpcHOST_IP_MALFORMED,
+	rpcLGR_IDXS_INVALID,
+	rpcLGR_IDX_MALFORMED,
+	rpcNICKNAME_MALFORMED,
+	rpcNICKNAME_PERM,
+	rpcPAYS_ACT_MALFORMED,
+	rpcPAYS_AMT_MALFORMED,
+	rpcPORT_MALFORMED,
+	rpcPUBLIC_MALFORMED,
+	rpcSRC_ACT_MALFORMED,
+	rpcSRC_ACT_MISSING,
+	rpcSRC_AMT_MALFORMED,
+
+	// Internal error (should never happen)
+	rpcINTERNAL,		// Generic internal error.
+	rpcFAIL_GEN_DECRPYT,
+	rpcNOT_IMPL,
+	rpcNO_GEN_DECRPYT,
+};
+
+Json::Value rpcError(int iError, Json::Value jvResult=Json::Value(Json::objectValue));
+#endif
+// vim:ts=4