#include "mgmtapi.h"
#include <stdio.h>

...

LPSNMP_MGR_SESSION hSes=SnmpMgrOpen("192.*.*.*","public", 1000 , 5 );

if(!hSes)
 {
  MessageBox(NULL,"Error SnmpMgrOpen","",MB_OK);
  return;
 }

 AnsiString Oid = ".1.3.6.1.4.1.5758.1.30.1";
 AsnObjectIdentifier AsnOid;
 if(!SnmpMgrStrToOid (Oid.c_str(), &AsnOid)) return;

 AsnInteger errStat =  0 ;
 AsnInteger errIdx =  0 ;

 SnmpVarBindList BindList;
 BindList.list = NULL;
 BindList.len =  1 ;

 BindList.list =
    (SnmpVarBind *)SNMP_malloc( sizeof(SnmpVarBind) * (BindList.len));

 BindList.list[ 0 ].value.asnType = ASN_NULL;

 SnmpUtilOidFree(&BindList.list[ 0 ].name);
 if(!SnmpUtilOidCpy(&BindList.list[ 0 ].name, &AsnOid)) return;

if(!SnmpMgrRequest(hSes,SNMP_PDU_GET,&BindList,&errStat,&errIdx))
{
 char Buf[ 255 ]; 
 DWORD Err=GetLastError();
 sprintf(Buf,"SnmpMgrRequest(): %d",Err);
 MessageBox(NULL,Buf,"Error",MB_OK);
 SnmpMgrClose(hSes);
 return;
}
        AsnObjectSyntax *AnyVal = &BindList.list[ 0 ].value;

	UINT Len =  0 ;
	BYTE *puData =  0 ;
	char *pString = NULL;

             Len = AnyVal->asnValue.string.length +  1 ;
             puData = AnyVal->asnValue.string.stream;
	pString = (char *) SnmpUtilMemAlloc(Len +  1 );
	
            if(pString != NULL)
	{
	  if (AnyVal->asnValue.arbitrary.length)
	 {
  	   strncpy(pString, (const char*)puData, Len -  1 ); // ??? тут вылетает!
     	   pString[Len] = '\0';
	 }
	}
SnmpMgrClose(hSes);
...

typedef struct {
    BYTE asnType;
    union {
        AsnInteger32            number;     // ASN_INTEGER
                                            // ASN_INTEGER32
        AsnUnsigned32           unsigned32; // ASN_UNSIGNED32
        AsnCounter64            counter64;  // ASN_COUNTER64
        AsnOctetString          string;     // ASN_OCTETSTRING
        AsnBits                 bits;       // ASN_BITS
        AsnObjectIdentifier     object;     // ASN_OBJECTIDENTIFIER
        AsnSequence             sequence;   // ASN_SEQUENCE
        AsnIPAddress            address;    // ASN_IPADDRESS
        AsnCounter32            counter;    // ASN_COUNTER32
        AsnGauge32              gauge;      // ASN_GAUGE32
        AsnTimeticks            ticks;      // ASN_TIMETICKS
        AsnOpaque               arbitrary;  // ASN_OPAQUE
    } asnValue;
} AsnAny;

И

typedef struct {
    BYTE * stream;
    UINT   length;
    BOOL   dynamic;
} AsnOctetString;

И

typedef unsigned char       BYTE;

BindList.list =
    (SnmpVarBind *)SNMP_malloc( sizeof(SnmpVarBind) * (BindList.len));

 BindList.list[ 0 ].value.asnType = ASN_NULL;

 SnmpUtilOidFree(&BindList.list[ 0 ].name);
 if(!SnmpUtilOidCpy(&BindList.list[ 0 ].name, &AsnOid)) return;