Asp.net loses connection to remote share

I have two webservers that rely on a single file-share to read/write files to. All three computers are in the same domain, and ASP.NET impersonates a domain-user to get the access rights to the share. The applicatin accesses the share via UNC-path

But the latest nights, there has been occuring some problems when the application tries to access the shares. A typical error-message is:

"The system detected a possible attempt to compromise security. Please ensure that you can contact the server that authenticated you. "

and:

"Network path not found"

But when I access the web-fronts via RDP, the problem disappears.

From stackoverflow

• Just a thought, what about a WCF (or similar) service in the file-share target? If a network resource (file share) is interrupted/lost, it can get wonky (for lack of a better explanation). Your best option is to create a service interface that you control.

• Do you keep the connections open the whole time? or reconnect on each request? Since you say it only happens at night, it might be when DHCP refreshes or issues with your DNS

  I have seen the need to use this hotfix before for server 2003 sp1 http://support.microsoft.com/?id=898060