Getting Line Number Of Text

I'm trying to find the line number of a specific piece of text:

do while textFileOpen.AtEndOfStream=false
if textFileOpen.ReadLine=text2Find then
foundAt=textFileOpen.Line
end if
Loop

But it keeps giving the wrong line number

What I'd like is foundAt to be 0 then if the line is found foundAt is to be the line number, if it is not found stay at 0

In the script above foundAt at increments even though the text isn't in the line?

I also get a "Input past end of file" if text2find isn't found