Text range Selection problem

Hi

I want to select some text in a textframe.

I am using this method

textFrame.characters.itemByRange(n,m).select();

but characters.ItemByRange();

give error member not found if I am using long Integer as a parameter in this.

for example my text is AdobeIndesign and i want to select Indesign in AdobeIndesign.

characters.ItemByRange(6,13);

How use characters.ItemByRange() to select text.

or there is another method to select a text range.

How use character or String type parameter in characters.ItemByRange()

Thanks.