Intermitant problems with passing form data

[YoUnG-D]

I am experiencing a rather strange problem, that occurs periodically in an ASP.NET application. Here's the scenario:<BR><BR>I have an ASP.NET application that passes a user-specific data value between pages using a hidden input field. I may have several users accessing the application at any time. To access the application, User A logs in. User B logs into the application while User A is logged in as well. After logging into the applicaiton, the user's staff id is used throughout the application and is passed from one page to another using a hidden input field and is displayed as text on the page. This works quite well 95% of the time. However, from time to time, something very wierd happens: sometimes as User A navigates from one page to another, periodically, User B's staff id will show up on the page, and in the hidden input field, where User A's data should have been.<BR><BR>I personally have been unable to re-create the problem, but I have had 5 different users bring it to my attention. This is a rather serious problem, because the staff id is submitted to the database in various form submissions throughout the application. The wrong staff id value in the hidden input field results in the wrong staff id value being sent to the database. The problem seems to occur two or three times a week, and at no particular time during the day (8:30am - 5:00pm). My server's cpu resources averages only about 3-5% max usage, and the speed of the application is fine as well. I have reviewed the server's Event Viewer, and there are no problems reported to it from the .NET framework, ASP.NET, or IIS. I have about 100 users of the application, 50% of whom access the application over the internal network, and never hit the internet to get to application. 4 of the 5 user's reporting the problem were using the internal network when the problem occurred, and 1 was on a dial-up internet connection. I am concerned about the persistence of this problem, and the possibility of it increasing in frequency. I have researched MSDN and several other ASP related websites, including this one, and have not yet come up with any reason as to why the problem occurs. I am considering the user of a session variable, but I would like know the cause of the problem, to insure that using a session variable would solve it or to also possibly avoid the overhead and disadvantages of using a session variable.<BR><BR>Your ideas and suggestions would be greatly appreciated.<BR><BR>alc