diff --git a/Classes/CSCountMapper.m b/Classes/CSCountMapper.m
index 594c874..ed2f9d9 100644
--- a/Classes/CSCountMapper.m
+++ b/Classes/CSCountMapper.m
@@ -13,7 +13,7 @@ @implementation CSCountMapper
 + (NSNumber *)transformValue:(NSArray *)inputValue {
 	NSAssert([inputValue isKindOfClass:[NSArray class]], @"Input Value needs to be Array");
 	
-	return [NSNumber numberWithInt:[inputValue count]];
+	return [NSNumber numberWithUnsignedLong:[inputValue count]];
 }
 
 @end
diff --git a/Classes/NSObject+CSAPI.m b/Classes/NSObject+CSAPI.m
index ad67e19..3441093 100644
--- a/Classes/NSObject+CSAPI.m
+++ b/Classes/NSObject+CSAPI.m
@@ -262,6 +262,10 @@ - (NSNumber *)NSNumberValue {
  */
 - (NSString *)NSStringValue {
 	if ([self isKindOfClass:[NSObject class]]) {
+        if ([self isKindOfClass:[NSNull class]]) {
+            return nil;
+        }
+        
 		NSString *retval = [NSString stringWithFormat:@"%@", self];
 		
 		return retval;