Hi
The first thing you should do if you havn't already is update Studio 9 with the latest patch (9.3.5). You can download it for free from
http://www.pinnaclesys.com/
The latest version is far more stable than earlier versions.
If you are getting lots of dropped frames you could check, through Pinnacle, that the performance of your HDD is OK i.e. you can read and write to your HDD at a suitable rate. Inability to read and write fast enough leads to dropped frames.
There are many problems which can lead to dropped frames, but from my experience, the most common is due to slow access to the HDD. I'm not sure what causes this but I've found the only sure way, on my system, to cure the problem is to reformat the HDD (I use a second HDD). This usually occurs on my system when the HDD become more than 50-60% full and hasn't been formatted for a couple of months.
If you check the FAQ's on the Pinnacle site it gives you additional methods to cure the problem of dropped frames.