my page always expired ?

Hi, I'm writing a website in PHP at home, no internet connection.Im using a single software that give me Apache server, PHP..I have a small forum,after user added a topic, I redirect him to homepage, then if he click back button in IE , IE will say that the page he requesting is expired ?:confused: It says that my page was created by infomation submitted in a form, to see that page it has to resubmit that information ?

I have tried with this forum, I answear in quick reply to a topic, it showed me my reply, then I go to another page on the menu, then I click back, the page is not expired ?I got the page before I posted my reply.

Can anyone explain this for me?

I didnt try to create problem but after I posted my topic, I go to homepage then click back, I saw my topic again in editing process, I click submit again and well there are 2 of them ?
I dont want this problem to occur with my site, any one can help me?

You might want to add another refresh in there to refresh to the page where your submitted reply is and then refresh to the homepage.

Thank you, I will try it today :)

I didnt try to create problem but after I posted my topic, I go to homepage then click back, I saw my topic again in editing process, I click submit again and well there are 2 of them ?

Delete the other topic if possible, if not report it to a moderator for them to do it