desktop mannager won't communicate 8820
 

I just bought a BB 8820 unlocked, it's made on Hungary and it shows on the screen a battery with a red line crossed, I know what the symbol means BUT the battery is OK, it's the right model C-X2 and I already tried it on a different phone and it's working fine. PLUS, the desktop manager cannot connect to the device,the application loader neater.
I download the 4.5 device software and had the VENDOR file erased too, I start running the "loader" from C:\Program Files\Common Files\Research In Motion\AppLoader. and it loads the JVM and system software but when it is initializing the device I get the connection error and that's it. FROZEN AGAIN.
I try to replace the USB cable, the soft and hard reset too, the BlackBerry Master Control Program and the JL_Cmder, diferent DM and Device software versions with no results.

The only thing different now after al that work is that after a while with the phone disconnected, when the "no battery" error cleans up and the screen goes black, if I reconect the device to the wall outlet socket or to the computer with the USB cable, the battery charging symbol appears =) (didn't do it before). But after a few minutes it f...s up again and the same "batterry error" appears, I can't communicate to the device.

HELP ME PLEASE!!!