Project is running well.But exe is failed to run.

[Sritanu _ Ghosh]

I am a Software Developer working on VS2008(VB.NET) and SQL Server2005.I am new comers on PDA(WM 5.0).When I run my program it works fine.But when I run it from Debug\Release\PDA.exe.Then I got this error "Top-Level cannot be added".What can I do for it.I have a parent form and four child form. :(