T43, charging issues on Port Replicator II.

[alpuzz]

I've had my T43 and port replicator for several months. Everything was fine until recently. Lately though, i'm noticing the following problem every couple days:

Throughout the day, I usually leave my T43 connected to the replicator and running. Every so often, when I come back to the machine, I am finding that the battery level has gone down to critical and that the machine has therefore gone into standby. If I bring the machine back up, I see that I'm not charging, and on battery power. I can get the machine to start charging again by fiddling around, pulling the AC power and reconnecting it to the port replicator and/or removing the laptop and docking it again. As far as I can tell, the connection to the port replicator is good and i'm lining the machine up properly. When I lock it into the replicator, I press on each side of the top of the machine until I hear a click. when I hear two clicks, one for each side, I'm assuming that the connection is as good as it will get.
What makes this really odd is that once the machine is docked, I sometimes don't touch or move it for several days. The machine will run happily on AC power for a time and then suddenly, the above problem will occur without my moving the machine or disturbing it physically in any way.

Any thoughts?

Thanks,