problems accessing XBee Explorer on Ubuntu

Hi,

a recent Ubuntu system update (Lucid 10.04.3 LTS) seems to have changed the locking procedure for the USB/serial port - /dev/ttyUSB0 - from which I have been accessing XBee Explorer modules.

Prior to the update I was accessing a number of modules - one at a time - at this port. Unplugging one and plugging in another was no problem. Each was accessible at /dev/ttyUSB0.

Following the update I am only able to access the first module connected. Thereafter I am unable to connect to any subsequent module; even the same one if it is unplugged and re-plugged.

To access a another module I have to reboot the system.

I think it might have something to do with the removal of stale lock files - I am reading data from the serial port with a Java programme using the RXTXcomm lib - but am not sure.

thanks in advance,

rbm

PS

Just to be sure, I have tried swapping modules whilst running the version of the OS immediately prior to the update, and there is no problem.