I just found a reason for the "authorisation failed" message on the mobile phone (Nokia N80), which was not stated on this boards before (or at least i didn't find a similar post):
if there is a problem with the memory card, the "authorisation failed" message appears on phone.
I do not know what causes the problem that suddenly the mobile phone does not recognize the memory card anymore, but when it is not accessible (tools/memory) or drive e: is not visible in pc suite's file manager , then the error message is displayed - if it is recognized correctly, then a dialog "install to " appears as it should.
We use that phone just for testing our applications, not for real usage. So it is quite strange why this happens - the phone has absolutley no sign of wear. Turning off the phone and reinserting the card usually makes the thing working again..