Web site open with Internet connections from out side

Hi to All, I am geting problem with Through the Internet Connection from server.we did asp.net Lookup control it is working fine in locally and local server,but we are getting problem with Internet like asp.net application is hosted in Server and running the that application out side like through the Internet.I have textbox behind that one Image when i click on Image it will display small popup form ,in popup form treeview control from that i am selecting value it is not retaing to that textbox.but it will working in locally.Please help me it is very Urgent ?...
 
Thanks, Narasima