Hi Jan,
To help us isolate the problem better, please capture the debug log, including the validation information, from within the GUI client.
On the GUI client menu, select 'Help' then 'Capture Debugging Log'. This should bring up a Debug Log window. With this window still open, please:
a) Select the SCM configuration, click edit, click validate, click cancel.
b) Reproduce the issue. Once the error appears, click 'Save Log' and send us the log. This will help us figure out what's going on.
Also, if you could include a screen shot of your SCM configuration screen and also clarify what you mean by the term "local mirror" in your previous post, that would be great.
I've created support case 71725 for this specific issue so please send these files to support@smartbear.com and include "case 71725" in the subject so it automatically gets tied to that case thread. Thanks!