Intermittent "The network path was not found." & "Logon failure: .


I am "intermittently" getting the "Logon failure: unknown user name or bad
password." and "The network path was not found." when writing files to
windows shares using UNC with IP Address (e.g. \\\blah\foo.txt)
from ASP.NET 2.0 C# Web App under IIS 6.0 on Windows 2003 SP2. I am using the
Impersonation and userid/password in the web.config that are valid on remote
shares. It works most of the time (I process about 50 requests/second);
neither the target server nor the source machine shows any event log
corresponding to these errors. I have also set the DisableDos registry entry
and there is no Symantec or other antivirus product running on this machine.
The target server shows only about 10% network utilization and 5% CPU. So,
everything is lightly used. Below is the code that I am using for writing the
files; any help would be appreciated:


FileStream outputStream = null;
outputStream = new FileStream(filepath, FileMode.Create);
// code for writing removed for simplicity...

catch (Exception e)
errorlog.write("Error processing images", "Failed to
open file: " + filepath+ " exception was: " + e.Message + " User: " +
if(outputStream != null)
outputStream = null;