Serial monitor error

I recently updated to the 1.6.3 IDE under Ubuntu 10.04 and all seemed well, though connecting to the device was a bit of a dance. I would often get an error saying that the board at /dev/ttyUSB0 was not available, and the Port menu item was greyed out. It would work after several disconnect, shut-down, reconnect, re-start cycles and stay connected. I can upload the code without errors, so I know that the connection is ok, but the serial monitor reports an error.

This became a pain tonight, and while looking for a cause (I checked groups and user permissions - all ok), I opened my original version of the IDE, 1.0.5, and had no trouble using the serial monitor.

If I use a serial terminal it runs fine too, so I'm looking for things to check in the set-up, hoping to find a difference between the two versions.

Has anyone had a similar experience? Could someone suggest where I might look for differences in the set-up?

Pogo.

[Edit]

I just downloaded and installed version 1.6.4 after noting a fix to the serial port detection, and the serial monitor works fine. I guess I'll just jump up one version...