Mapped drive not available

We have a vb.net program.
It uses mapped drived.
I have a drive called P:
sometimes my program will not be able to see the drive and if I go to
explorer it will have a red x by it. I can then browse to it and see it
fine, but our program still cannot see it.

I have a dialog browser in the program and when I open it and go to my
comptuer, all of the mapped drives have red x's by them. If I click one to
access it then all is ok until it times out again.

We have the program installed on many computers but only the vista computers
are having this problem we have never had a problem with the xp stuff.
Also the code that checks if the directory is available checks both the
local drive and network drives and only the network drives have this problem.
We use
my.computer.filesystem.driectoryexists("P:\test")



is there a way to either refresh the network connections or tell them to not
TIMEOUT.