error '80070002' when calling dotNet DLL

Hi all.

Im receiving a very strange, un informative and very ****** annoying error message when i try to create an instance of a .net DLL from an asp page.  Here is the code i use:

Dim objThumbGen
Set objThumbGen = Server.Createobject("DigiThumbGen.CThumbGenerator")      ---> LINE 312

objThumbGen.ExecuteThumbGen Session("JobId"), Session("templateId"), qryView, appPath, tlgConn, dpConn, outputBase, relativePath, log, defaultImage
set objThumbGen = nothing

the strange thing is that i have 2 virtual directories pointing to the same folder, and if i run the page from one VD then its fine, however if i run it from the other i get this:

error '80070002'
/guildonline/digitalprint/TemplateOptions.asp, line 312

if i restart IIS on the server it works once, then it gives me this error again!?!

Does anyone have any suggestions?

Thanks

Apresto

FYI:   DLL Language C#, Classic ASP Page