I was trying to make a presentation using beamer, when suddenly I got the following error message:

I don't know why it does this, because I've never had to use sansmathaccent before.
I tried running old files that used to be fine, however they get the same error message now as well. Even the most simple of files:
\documentclass{beamer}
\begin{document}
\frame{Hello $A$}
\end{document}
gets the error message. What is/could be going on?
N.B. I recently (two days ago) ran an update for all my packages. Could this have something to do with it?
Edit: By now I've installed both sansmathaccent and filehook because the error message said so. Now it shows this error:
!pdfTeX error: pdflatex.exe (file mathkerncmssi8): Font mathkerncmssi8 at 450 n ot found ==> Fatal error occurred, no output PDF file produced!
as soon as you include any maths to the document. Note If i type Hello $\mu$ everything is fine. Ordinairy letters are causing trouble.
(/usr/local/texlive/2014/texmf-dist/tex/latex/sansmathaccent/sansmathaccent.sty Package: sansmathaccent 2013/03/28If you use texlive or miktex try using the package manager to install or update sansmathaccent? – David Carlisle Oct 24 '14 at 12:43sansmathaccent. Now it wants me to installfilehook. I find this all very strange, since I never had any problems with beamer so far. And as I said: even files that used to run fine, now don't anymore... – gebruiker Oct 24 '14 at 12:47sansmathaccentshould work fine: it certainly seems to for most users. – Joseph Wright Oct 24 '14 at 13:52