Max Limit of post variables

I am trying to generate an html form with approximately 3000 post variables (1500 input type text and 1500 hidden, I am mimicing a grid control). The page will handle several hundred but it crashes with more. Is there a limit to the number of variables that can be sent post. Or is it possible I am violating some html tag rules and the browser does not have a too much problem with the few hundred post variables. I am using apache2, php4 and Explorer for the browser, however it also crashes in Netscape (but not as bad). Stuart