VS 2008 LNK 2028 errors

Error	1	error LNK2028: unresolved token (0A000009) "void * __clrcall memrealloc(void *,unsigned int)" (?memrealloc@@$$FYMPAXPAXI@Z) referenced in function "public: int __clrcall Signal::undo_difference(class Signal *)" (?undo_difference@Signal@@$$FQAMHPAV1@@Z)	SIGNAL.obj

extern void *memrealloc ( void *ptr , unsigned int size ) ;

extern TDecoratedMDIFrame *frame ;
extern npredictMDIClient  *mdiClient ;

class Signal {

public:
   Signal ( char *signame , int length , double *signal ) ;
   ~Signal () ;

   enum SignalType type ;  // Optimizes display
   int n ;             // Length of signal
   char *name ;        // Its name
   double *sig ;       // It is here
   int centered ;      // Has it been centered?
   double cent ;       // Its center if so
   int detrended ;     // Has it been detrended?
   double slope ;      // Slope if so
   double pivot ;      // And pivot point
   int offsetted ;     // Has it been offset?
   double offst ;      // Offset if so
   int scaled ;        // Has it been scaled?
   double scal ;       // Its scale if so
   int standardized ;  // Has it been standardized?
   double mean ;       // Its mean if so
   double std ;        // And its standard deviation
   int differenced ;   // Has it been differenced?  (Degree if so)
   double leads[3] ;   // First points before differencing
   int seasonal ;      // Has it been seasonally differenced? (Period if so)
   double *sleads ;    // First period points if so
   int source_n ;      // If CORRELATION or SPECTRUM, length of defining signal
   int known_n ;       // Normally n, else set by NET_PRED.CPP, ARMAPRED.CPP
   int npred ;         // Number of future prediction confidence intervals
   double *intervals ; // This is them (2 * npred long), alloced in NP_CONF.CPP
   int mult_conf ;     // Normally 0, 1 if 'intervals' are multiplicative

   void replace ( int n , int n_protect , double *x ) ;
   void center () ;
   int median_center () ;
   void undo_center ( Signal *per ) ;
   void detrend () ;
   void undo_detrend ( Signal *per ) ;
   void offset ( double val ) ;
   void undo_offset ( Signal *per ) ;
   void scale ( double val ) ;
   void undo_scale ( Signal *per ) ;
   void standardize () ;
   void undo_standardize ( Signal *per ) ;
   void difference ( int degree ) ;
   int undo_difference ( Signal *per ) ;
   int seasonal_diff ( int period ) ;
   int undo_seasonal_diff ( Signal *per ) ;
   void integrate ( int period ) ;
   void siglog () ;
   void sigexp () ;
}

int Signal::undo_difference ( Signal *sigptr )
{
   int i, pass, passes ;
   double temp, sum, *dptr ;
   remove_display ( this ) ; // Windows must remove MDI child if displayed
   if (sigptr != NULL) {
      if (sigptr->differenced)
         passes = sigptr->differenced ;
      else
         return 0 ;
      }
   else
      passes = differenced ;
   MEMTEXT ( "SIGNAL: undo_difference" ) ;
   dptr = (double *) REALLOC ( sig , (n+passes) * sizeof(double) ) ;
   if (dptr == NULL)
      return 1 ;
   sig = dptr ;
   
   for (pass=0 ; pass<passes ; pass++) {
      if (sigptr != NULL)
         sum = sigptr->leads[passes-pass-1] ;
      else
         sum = leads[passes-pass-1] ;
      for (i=0 ; i<n ; i++) {
         temp = sig[i] ;
         sig[i] = sum ;
         sum += temp ;
         }
      sig[n++] = sum ;
      }
   type = DataSignal ;
   known_n += passes ;
   return 0 ;
};