Ok,
i finally got it to work with my pc. It took about 20min for my PC to discover it. After connecting I opened up the terminal (the USB serial one was already open). After I did that it again took 5mins. After that it finally showed Connect:OK 
.
The connection to my HTC Wildfire S still dosnt work. I think its cause Connecting takes so long (or discovering the device?!?).
Is there a way to speed up the process, so my sellphone can discover the shield?