I resolved this myself...and WHAT a hack I have had to perform! I am sorry SharePoint is not a well constructed product at ALL!
Anyway, the solution revolved around the Application Pool bound to the main SharePoint database... basically I was able to replicate the error by recycling the Application Pool! The setting for recycling was to be completed once a day in the middle of the night...
So the solution I found was to manipulate the global.asax and FORCE the retention of the SessionID through adding a Session_Start function and temporarily binding a variable to the Session.SessionID...once updating the asax file I recycled the Application Pool then opened a client side Internet session and accessed the Forms Library stored on the SharePoint Intranet site...a new or existing item opened without problem!
The global.asax now looks like:
<%@ Assembly Name="Microsoft.SharePoint"%><%@ Application Language="C#" Inherits="Microsoft.SharePoint.ApplicationRuntime.SPHttpApplication" %>
<script runat=server>
void Session_Start(object sender, EventArgs e)
{
//Code that runs when a new session is started
string sessionId = Session.SessionID;
}
</script>