strange loader issue

i've always started lotro from a bound hotkey with no problem until recently. now when i use the hotkey i get all the way to connecting to server then an error msg stating.. can't open the data files. check that they exist and that you have permission to write to them. the program will now exit (201).
this problem occurs with both the invoker and launcherbut if i start the game from a desktop shortcut no such problem occurs.
as i've not changed anything at my end i'm stumped
anyone else with this issue?
thx