If you mean "water in the emergency brake froze the shoes and it
snapped free when I drove forward" then I would not worry about it. If
you think you have a basic brake system problem, then have it checked.

If you get the brakes wet when driving (and shortly before stopping)
they will be wet when you park. Saab uses a separate system for the
emergency brake and it will not dry out by application of the foot
brake. It takes a little while and dries as you heat (use) the normal
(road) disk brakes. So, if you get it went then park it wet, then the
temp drops, it's not surprising that it freezes up. It can also
happens when there is a lot of rain or moisture in the air and then
there is a big temp drop.