What the Sony post means is that you are not using the latest version of the XDCAM Transfer tool. For some decimal-system-defying reason, the version after 2.9 was 2.10 and not 2.91 or 3.0.
Unfortunately, this does not solve the thumbnail problem (It is a bit weird that this only affects some machines. I’m wondering if it isn’t an obscure bug in a graphics card driver, or something).
I have just read on another forum that Sony have released an SxS driver for Snow Leopard, which is available here:
https://www.sony.ca/promedia/drivers.htm
The XDCAM Drive software for the PDW-U1 doesn’t work at all on Snow Leopard. If they are having the same problems with the FAM driver (I have no way of trying it), which is part of XDCAM Transfer installation, then maybe this is causing the delay in releasing a new version.