Just a quick workaround for invalid chars in note titles:

OpenInMarked.scpt chokes on nvALT filenames with invalid characters (since the actual filenames get replacement chars, but the note title retains the original chars, and the script uses UI scripting to grab the note title to try to find the actual file).

In my case, my note title had a ":" which was replaced with a "-" in the actual filename. Adding the following to OpenInMarked.scpt helped it find the file correctly.

on replace_chars(this_text, search_string, replacement_string)
    set AppleScript's text item delimiters to the search_string
    set the item_list to every text item of this_text
    set AppleScript's text item delimiters to the replacement_string
    set this_text to the item_list as string
    set AppleScript's text item delimiters to ""
    return this_text
end replace_chars

Then, immediately after setting p to the UI-script-derived note title,

 try
        set p to my replace_chars(p, ":", "-")
    end try

I imagine this same process could easily take a list of other invalid chars besides ":" to help make sure the file opens.