wap data with nextel network not running

I have created an application for wap enabled devices that is meant to be run on nextel devices.The application is created using wml and asp.The application is not running on nextel devices and it gives an http:500 error.
Do i need use some speical tags for creating wap site.We have tested the application using PDA as well as by downloading openwave simulator by using wap as well as httproxy settings.The application is running fine but not on nextel devices.
Is there any different specification for nextel wap gateway.
i have created the application using wml and asp and ms-asscess as backend.
sometimes the page runs and sometimes the same page gvies error.