Peter,
About 2 months ago or so, I downloaded your 3.44 version of FSUIPC to be compatible with the FS9 Update. When I did that and installed it, I began to have problems with aircraft just freezing in one position after 5 minutes.
I'm not running the fully registered version, but I have put in the key for Squawkbox. The reason I bring this problem here is because this all began right after I installed the FSUIPC. For over a year, I've never had a problem, until I installed the 3.44 version.
I know it isn't SB, because I've reinstalled that, went to the old default CSL files, and then finally I also reinstalled FS9. If you have an older version of FSUIPC I could have to try and see if this is the problem, I would greatly appreciate it. That or whatever other solution you might have to keep from resorting to that. Thanks.