>I ran my stuff fine on my development box (NT4Wks, PWS, PIII650-256mb RAM) and held down [F5] in IE to make it refresh a lot and it was all good. Then tried it on the development web server (NT4Svr, IIS, PI233-128mb RAM) and when I held down [F5] on occasion I would get simple black Times text on a white background "the requested resource is in use".

In your IIS settings, do you have "Cache ISAPI applications" checked? The setting is in the website properties, under Home Directory, click the "Configure" button.

If this is not checked, IIS unloads ASP (and all other ISAPI apps) after every hit, and hits in quick succession will cause the error you are seeing, because one hit comes while ASP is still unloading.