The problem seems to be related to the filename used in the ReadTextFile() function. Without further knowledge how this string is obtained, we hardly can say something definitely on the reason of this issue. It may be worthwhile to add a call to MessageBox() to output the calculated filename before applying ReadTextFile() to narrow the case.

Note: The forum may not be the best place to post specific problems or bugs, since without an email address we can’t ask for further clarification.