From a previous posting by David Kruse [MSFT]:
Can you check if the webclient service is running? Webclient allows you to
access DAV shares via HTTP as a normal file system. However, the timeouts
for DAV/HTTP are a bit different than that of traditional SMB, which can
result in what appears to be hangs. There has been some updates that can be
applied to the client as described in the KB articles below. Also, you can
try disabling the webclient service in the short term to see if that solves
the issue.
The reason many people see this on just the first access is, after the first
access the UNC providers cache the knowledge that "this share is handled by
SMB, not DAV" and DAV is not involved until this cache expires.
http://support.microsoft.com/default.aspx?scid=kb;en-us;812924
http://support.microsoft.com/default.aspx?scid=kb;en-us;312181
Type the following command to determine whether webclient is running:
sc queryex webclient
If the STATE shows RUNNING, then run the following command to disable it:
sc config webclient start= disabled
The initial connect issue should not occur on the next boot. To avoid a
reboot, you could run the following command:
sc stop webclient
Hope this helps
Arvind