Comment 13 for bug 1360200

Hmm, nothing suspicious in that log, the errors are simply from third party calibre plugins that have not yet been updated for calibre 2.0

I suspect this is just some fundamental incompatibility between Qt 5 and some windows XP machines. I do have Windows XP running in a virtual machine myself, in which calibre works fine, so it is a little hard for me to be more specific. I suggest you stay with calibre 1.48 until you decide to upgrade your windows. Unfortunately, since Microsoft has dropped support for Windows XP, it is becoming harder to get modern software running on it.