perhaps no real insights, just a couple of guesses:
first, i noticed it's a DOS disk you're having trouble with... this may have nothing to do with it, but i remember there being an eight character limit to filenames in DOS, and although the DOS system may still recognize the full name of the file, i think the mac os would only see the truncated form (such as "the_coo~1" in your example), and it seems like the script is having trouble locating this file/folder when it chokes (otherwise it would go ahead & fetch the list). on the other hand, the script should see the files as the DOS disk is displaying them, unless it's looking for a specific name of an item... which brings me to the second wild guess:
although it looks like that script is assigning variables instead of working with direct file/folder names, if properties, or variables, are set up in a script at the top level (no run handler (on run...)) or in the main run handler, the first time the script is run, the results of the variables will be stored/cached in the script (a long standing applescript faeture/bug), such that in your example, the second time the script is run, it will be searching for a specific folder, and if not found, it will generate an event error & quit. however, if it seems to work fine in mac os scanning folders always with different names, then this probably isn't the problem. if you're not sure if this is the case, you could force the variables to be local (not retained by the script) rather than global by including a line for each of the form:
local these_items
local this_folder
at the top level of the script (not within a "handler") or within the run handler.
hope this helps-
cheers, acur