If you create a VI in LabVIEW 7.0 (or 7.1) containing the Write To Measurement File Express VI (formerly called "Write LabVIEW Measurement File") then save it and open it in LabVIEW 8.0, you should be able to open its configuration page without error.
Do you know if this error would be seen opening that VI from 7.1 on any computer, or just your one particular machine?
I'm not sure if I'm clear on what you were doing, but if this was not working for you, I'd be interested in taking a look at the VI that was having problems. For simplicity, if you would be able to take the VI you were having problems with, delete everything out of it except for the Write To Measurement File Express VI that is giving you problems, then save as a new name and attach it to this thread, along with any steps needed to reproduce the error, that would help us help you the best.