windows 64bit problem

I have developed a windows application using C# VS 2008 and Sql 2005 express, i have testes the application on my machine and it works fine, 开发者_运维技巧my machine is win32 bit, when i tried the application on windows 64bit it keeps giving me an error message on the start of the application,although i installed the sql express on that machine but should i install .NETframwork3.5sp1 64 bit also? , the target machine is widows 7 64bit, also is there a technology or a way to make the application work in the following sequence: 1- the CD is auto run 2- the setup checks for the installed prerequists and install any necessery one without the interference of the user. one last question,should i rebuild the application on an 64 bit machine to make it work on 64 bit machine? thankx

In your build Settings, change from "Any CPU" to "Win32". You most propably use some native API calls which will load native DLL's. YOu can't load a 32bit DLL into a x64 process, so that will fail, if .NET scales your application up to 64 bit. Compiling with the Win32 setting will prevent .NET on the target mashine to scale your application up.