Connection Problem via USB "The port COM2 could not be opened: Port in use"

Hi,
since 4 months i have a problem. I cant test my apps from qtCreator via USB on my Nokia E7.
E7 was new flashed. QtCreator is up-to-date.
QtCreator recognise the phone if its pluged in.

On the config window "symbian-devices" > "Run" > "Communication Channel" > "Serial: Serial port: Nokia E7-00 USB Serial Port (COM2)"

On click at the testbutton in the corner i get a message with a red background: "[B][COLOR="red"]The port COM2 could not be opened: Port in use[/COLOR][/B]"

What can i do?!

QtCreator: 2.4.1 (Qt 4.7.4 32bit)
E7: Symbian Belle / 111.030.0609

now... 2 days later, i format my pc and installed all things new.
But now...
"symbian-devices" > "Run" > "Communication Channel" > "Serial: Serial port: Nokia E7-00 USB Serial Port (COM3)"

On click at the testbutton in the corner i get this message:
---------------------------
Waiting for CODA
---------------------------
Qt Creator is waiting for the CODA application to connect.<br>Please make sure the application is running on your mobile phone and the right IP address and/or port are configured in the project settings.
---------------------------
Cancel
---------------------------

Here the Screenshot, where everybody can see, that i choose "Serial" not "WLAN"...
simply anyway what i choose...
On my Phone "Coda (driver: Legacy (4.0) V 4.0.23)" is running!
damn... i dont know... what can i do?

[IMG]http://www.abload.de/img/qt_errors1yt3.png[/IMG]