What Is This Pleas Tell me What can i Do

1>------ Build started: Project: Code, Configuration: Debug Win32 ------
1>LINK : error LNK2001: unresolved external symbol __DllMainCRTStartup@12
1>c:\documents and settings\owner\my documents\visual studio 2010\Projects\Code\Debug\Code.dll : fatal error LNK1120: 1 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

use google and define a dllmain.

There is something else wrong with it (even if it might fix it), since DllMain is optional.