VB.net publishing forms

Answer 1

System.DllNotFoundException: Unable to load DLL 'xpcom'

Your program has a dependency on unmanaged DLL(s), the ones that implement the browser. Visual Studio cannot find these dependencies automatically. Xpcom.dll is indeed one of the components that get used in Firefox. There are probably some additional ones.

You need to find the deployment instructions for the gecko library you are using. To get these DLLs published, use Project + Add Existing Item and navigate to the DLL. The Build Action property for the item should be set to "Content", it is by default.