Calling F# from Excel 2002/03: "Automation error"

I'm trying to call F# from Excel (2002) but get "Automation error" when I try to create a new instance of my class. I run regasm in post-build, add reference, placed Excel.Exe.Config in Office10 folder (with .NET version 4.0.30319.1) and this is my class:

[<System.Runtime.InteropServices.ComVisible(true)>]
[<System.Runtime.InteropServices.Guid "F348766A-B63D-41FE-824C-27989266A535">]
type Provider () =
    member __.Compile s = Compiler.compile s

And the Compiler module has its own attributes with a different Guid. The error is in this line:

Set p = 开发者_如何学运维New MCTE.Provider

Any ideas?