This is rather difficult to explain in words, but I'll try.
While experiencing the error reported in this thread, I Alt-TABbed to another process to write down some notes in order to report the error.
1) The error msg dlg remained on top of everything (not surprising, usually can be managed)
2) No mouse cursor appeared (it was hidden in the RW launch screen), making quite hard to use any other application or even dragging the error dlg out of the way
3) It was not possible to Alt-Tab back to the error dlg to acknowledge it, shut RW down and go on. In fact, I ended up turning the machine off with Ctrl-Alt-Del (luckily the keyboard was not grabbed).
Possibly it is not super-important, but being forced to turn off a machine to recover from an error msg is not very user-firendly...