If you try to use marvosym with MikTex, you might run in the following error:

Trying to make PK font umvs at 657 DPI...
Running miktex-makemf.exe...
miktex-makemf: The umvs source file could not be found.
Running ttf2pk.exe...
miktex-makepk: PK font umvs could not be created.
Process exited with error(s)

But the solution is quite easy: just start a commandline and navigate to your MikTex installation. Then enter the bin folder and execute these commands:

initexmf --mkmaps
initexmf --update-fndb

Afterwards, everything should work fine.