Reader 10.1 "Failed to load an application resource"

Hi

I upgraded from Reader X (10) to 10.1. Since then every time I start it, whether as a standalone or plug-in, I get one or more instances of an error message which says "There was an error during initialization. Failed to load an application resource (internal error)." I also note that there is no plug-ins menu.

This is getting annoying, to say the least. I am running Windows Vista SP2. Googling produced nothing relevant.

Does anyone have any ideas?

Thanks

Luke