On my machine .asp does not have any file association. "Open with" is blank. Check out this site:

[Link: w3schools.com]

Perhaps try clearing the browser cache before entering the Harmony website. If the site is loading from the cache it could be referencing invalid items. Also, when you try to change an item "open with" does SeaMonkey or a program in that suite appear in the drop down list of available programs? That could help you isolate which program to remove.