while (my $line = <$log>){
   if (/recvd AA_BIN_MSG_VER_CHG/ .. /?:(Prepared to Send OK|Sending Invalid credential)/){
      if (/Handling NSPAdvice for mechanism \[4\]/ .. /whatever_condition_to_reset_this_block/) {
          if ($line =~ /Authentication mechanism returne
+d \[(\d+)\]/) { 
             my $errorCode = $1; 
             print "$errorCode\n"; 
             $ArcotIDError_Count++ if ($errorCode != 0 && $errorCode != 1); 
          } 
      }
   }
}