无法在VS2008中向F＃项目添加dll文件引用

I can't seem to add a reference to a DLL file in F#. It might be a bug with Visual Studio. I attempted to add a reference to my F# project by clicking on "Add Reference" -> "browse". I found my DLL, and when I attempted to add it, nothing happened. The window didn't even close to confirm my selection. Help please.I can't seem to add a reference to a DLL file i