Problem with Text from HTML page

Hi,

I am using this function to read the the text from Internet Explorer,

It works good until now.
After this I use this function to search a specific string in this text:

The problem is that it is doesn't recognize on some cases the string to find, even when I see the string is actually there on the HTML page.
(MsgBox not shows all the text due to screen limitation and there is no scroolbar to the popup to debug)

I have 2 question:
1) Is there a limitation of the text which fetch from the BODY of the HTML with the _IEBodyReadText($oIE) function?
2) Is there a limitation of the text which can works with the StringInStr function?

Thanks.