diff --git a/pkg/rpc/request/txBuilder.go b/pkg/rpc/request/txBuilder.go
index 044db0b2e..e98afec8f 100644
--- a/pkg/rpc/request/txBuilder.go
+++ b/pkg/rpc/request/txBuilder.go
@@ -97,7 +97,7 @@ func ExpandArrayIntoScript(script *io.BinWriter, slice []Param) error {
 			return fmt.Errorf("parameter type %v is not supported", fp.Type)
 		}
 	}
-	return nil
+	return script.Err
 }
 
 // CreateFunctionInvocationScript creates a script to invoke given contract with
diff --git a/pkg/rpc/request/tx_builder_test.go b/pkg/rpc/request/tx_builder_test.go
index b5d056667..62ae926d1 100644
--- a/pkg/rpc/request/tx_builder_test.go
+++ b/pkg/rpc/request/tx_builder_test.go
@@ -135,6 +135,10 @@ func TestExpandArrayIntoScript(t *testing.T) {
 		{
 			{RawMessage: []byte(`{"type": "Array", "value": null}`)},
 		},
+		{
+			{RawMessage: []byte(`{"type": "Integer", "value": "` +
+				new(big.Int).Lsh(big.NewInt(1), 255).String() + `"}`)},
+		},
 	}
 	for _, c := range errorCases {
 		script := io.NewBufBinWriter()