Render in FCP's latest upgrade

Since upgrading I find I can't export with Quicktime movie or Quicktime conversion without it failing over a template from motion.

Also, using Compressor I sometimes get quicktime error -50 come up.

Sometimes. Not always. So I set it rendering again until it works.

A friend also complained about weird rendering issues.

Is this a bug? I'm on my second set of upgrade disks because the first would not work. And my second set only the basic install worked but not the content disks. I'm waiting for replacements there.

So... could I just have some incompatibility between the old content and the update?