Updating virus definitions: Icon not animated: Updating program

In Avast 5, with automatic updates switched off, manual updates of virus definitions usually take me less than 10 minutes. Sometimes, however, the process gets stuck at the “initialising” stage for as much as 30 minutes, if I let it run for as long as this. If it is still initialising after 5 or 6 minutes I usually cancel and start again with satisfactory results. Does anyone know how to avoid this problem?

Sometimes, after I have started a manual update, a pop up notice tell me my virus definitions are out of date and I should up date them. I ignore this. Should I do otherwise?

Although I have ticked “animate the icon when scanning”, the a-ball icon never rotates. Should I be worried? What can be done to fix this?

I am currently running Avast version 5.0.545 and the Summary Screen is telling me to upgrade. Before doing so, how can I find the version number of the new version, the size of the file to be down loaded and, most important, the changes, if any, to the system requirements?

Latest version is 5.0.594, size will be around 750kb, no changes to the system requirements…!
asyn