From the main Machform Admin Screen
1) Choose the particular form with the incorrect entries.
2) Click "Entries"
3) Choose the magnifying glass icon - near the left of the table displaying that form's entries
4)This will give you a new view of the entry.
5) Choose "Edit" option from the right hand side menu (menu should have a yellow background).
6) Edit each field and make the changes required, then click "Save Changes"
7) the screen will revert back to the "view entry" mode and should show the changes made.
8) Back-track to the main screen (using the bread-crumb navigation)and do your export to Excel etc that you need to do.
Note: this is version 2 instructions - they may differ from version 1.2.
See http://www.murraywebs.com/kb/entry/23/ for screenshots to assist you.