"Unknown error" when accessing password protected

[bveldkamp]

When I try to reopen a file from a password protected share (after a reboot) TextPad tells me an unknown error occured, instead of asking for a password.

To reproduce:
1. File | Open.
2. Type in a UNC path for which you need a password (i.e. \\otherpc\c$).
3. You're asked to provide a username/password for that path (I think that's a built-in Windows dialog).
4. Open any file form that path.
5. Log off and on (or reboot).
6. Start TextPad.
7. File | Choose "recently used" file.
8. TP shows a messagebox with "An unknown error occurred".

Expected result:
TP should ask for a username password.

If I browse to that path in Windows Explorer, I'm asked for a username/password, after that, I can reopen the file in TP without a problem.