Sometimes Evince. Sometimes Adobe Reader

[marc]

When I open a local PDF doc via Nautilus or from the desktop, it opens 
in Adobe Reader - as it should.

When I open a PDF via Nautilus that happens to be on a Samba share, it 
opens in Evince - which is shouldn't.

In both cases, the 'Opens with' tab from Properties is identical and 
indicates that Adobe Reader should be used.

Any ideas how this can be fixed?

And what might the more general problem be?

-- 
Best,
Marc