Have a look at https://groups.google.com/forum/?fromgroups=#!msg/comp.text.tex/ c8B-57irOaY/ecy76Jcr9LgJ
There was a bug in MiKTeX involving broken font packages. I would have thought it fixed by now, but perhaps not. The answer back then seemed to be to install the symbol package (or maybe, if that fails or if it's already installed, the ly1 package). Paul
