No Jira issues imported

Hi,

I just installed the trial version of YouTrack 4.0.1, build #3875 .
I registered for a trial license, here the details from the "Settings" page in the Administration section:
User Count    Unlimited     11
Reporter Count    0     0
Project Count    Unlimited     2
Issue Count    2147483647     2 (0.00%)
Disk Space    Unlimited     Unknown
Ban Guest    Allowed    
Https    disabled    
License expiration date     06 Oct 2012    
Free updates till     06 Oct 2012

If I try to import a project from Jira (Enterprise Edition, Version: 3.13.5-#360), the import process finishes immediately and does not import any issue from Jira. There is no error message.

Users are imported and are shown with subtext "Jira Login: username", groups are imported, the project is created, but the project count is not updated (Projects (Project count) ).
If I click into "Projects" - "<name of imported project>" there is the message "Project is being imported now or failed to be imported earlier, you can't edit it."

I played around with the import settings (Import Security Settings and Import Components as Tags) after deleting the project again, as well as to re-import with the once created youtrack project in place (it is saying, that it will only import new issues) ... - but never there is any issue imported at all.

I also checked the log files, I couldn't see any exception, it just stated, that users have been created, it does recognize components ...

Do you have any idea?

Thanks!

Martin