C# - Cant read/load more than 256 rule pharse in xml file

C# - Cant read/load more than 256 rule pharse in xml file

I am using a c# application to read/load from a xml file
Here are the xml file content, like from this example
http://msdn.microsoft.com/en-us/library/ms723634%28v=vs.85%29.aspx
<GRAMMAR>
<DEFINE>
</DEFINE>
<RULE NAME="HelloWorld" TOPLEVEL="ACTIVE"><P>HelloWorld</P></RULE>
<RULE NAME="HelloWorld2" TOPLEVEL="ACTIVE"><P>HelloWorld2</P></RULE>
<RULE NAME="HelloWorld3" TOPLEVEL="ACTIVE"><P>HelloWorld3</P></RULE>
</GRAMMAR>
and so on until rule pharse HelloWorld256, my application still can
read/load it, but after add the 257 rule pharse, it cant read/load
anything, is there a way so i can add more than 256 rule pharse in a xml
file?
Or maybe the alternative way, by open 2 xml files together, that each have
256 rule pharse, this is my c# application part, that load the grammar
// load the grammar SAPIGrammarFromFile("XMLhelloworld.xml");
I already tried these but no one works
// load the grammar SAPIGrammarFromFile("XMLhelloworld.xml");
SAPIGrammarFromFile("XMLhelloworld2.xml");
// load the grammar SAPIGrammarFromFile("XMLhelloworld.xml") &
("XMLhelloworld2.xml");
// load the grammar SAPIGrammarFromFile("XMLhelloworld.xml" &
"XMLhelloworld2.xml");
Please help which ever methode that can works