Welcome Back!
The "Timers getting out of sync" problem was one that was raised very early on, and commonly referred to as "clock drift." It is caused by variations in the 60Hz power cycle, and there isn't much that you can do to fix it. A few users had experimented with adding a few capacitors in strategic places on the board inside the CM15A, but that's about it.
Another solution is to keep the CM15A plugged into a running PC 24/7 (which is needed for most of the newer plugins, anyway). You don't need to keep AHP open, as long as the X10nets service is running. The service will sync the CM15A's time with the PC every two hours, which should correct any clock drift issues.
As for the updates, there have certainly been a lot of them since March of 2010. X10 brought in a new development team, so they were able to fix a number of issues with the software, and put out a whole batch of new plugins.
Unfortunately, one of the bugs they haven't yet fixed is the "Check for Update" function. It has been broken for a few years, so you need to go to the website to look for new updates.
Here is a link to the forum thread which lists the current bugs, as reported here by the users:
http://forums.x10.com/index.php?topic=22373.0When users report new bugs, they get added to the list (assuming they can be confirmed as a true bug, and not a one-off problem for only that user). When they get fixed, that is noted, as well.