P910 & SE Device Explorer

Hi,

I've just bought a P910 and, being a programmer, I'd like to use J2ME
to start developing MIDlets... Unfortunately, I'm not even able to use
Device Explorer, and to be precise, Connection Proxy. When I use
craddle USB cable, I set it to the appropriate COM port (the one I
could see in Phone Connection Link, which I disabled first); however, I
always get the following error (when pressing Connect button):

[Sat Jul 02 01:59:26 CEST 2005] SLIP.issueATCommand() Timed out reading
response to AT Command! num=15
[Sat Jul 02 01:59:26 CEST 2005] data =
OK

ERROR

[Sat Jul 02 01:59:26 CEST 2005] error creating
SerialSocketController(4)
[Sat Jul 02 01:59:26 CEST 2005] com.sonyericsson.sdkme.io.eslip.a:
Timed out reading response to AT Command!
[Sat Jul 02 01:59:26 CEST 2005] stopping sstcp mode
[Sat Jul 02 01:59:26 CEST 2005] eslip.closeCommPort start
[Sat Jul 02 01:59:26 CEST 2005] eslip.closeCommPort calling
stopSstcpMode()

Besides, if I use infrared connection, I get about the same error...
I don't tried BlueTooth, my laptop lacking BT support.

As I cannot find any article/post about such a pb, I thought it would
be simple, but I spent almost en entire day on this issue without
result... Anyone, an idea ?
Note: I did set P910 IR and Cable settings to modem; is it OK ? If I
set it to PC Connection, I get a different error, but no success...

PLEASE, HELP. THANKS