BitPim needs to speak to your phone using the correct serial port. Your phone needs to respond on that port. You should verify from the comm port settings dialog that he relevant port is available and the correct drivers are in use.
Note that software like Palm Desktop and ActiveSync like to grab ports. If this happens, temporarily disable the offending device.
On Linux you need to ensure that permissions on the device files are set so that your user can read and write to them.
Once you are using the correct port, you should check that the phone is responding. If you look in the log view you will see what errors are happening. The protocol log view gives even more details.
If your phone is not sending back any data at all you may need to configure something on the phone. Read the section about your phone cables for any specific information.
If your phone is responding, but BitPim is not understanding it, then there may be an issue with BitPim. Please grab a protocol log and submit it as described in support.
BitPim 0.62 06 November 2003