I'm trying to compile the C# sample project from Ascom website: http://ascom-standards.org/.
However, using DriverAccess; gives me problems since the compiler cannot locate the dll in the path specified at installation (all done automatically).
Conformance checker validates my Ascom Platform (the latest, 6 sp1).
I can't figure how to solve this.
You will need to add the reference. Project + Add Reference, Browse tab, navigate to c:\program files (x86)\common files\ascom.net and pick ASCOM.DriverAccess.dll. Drop the (x86) part of the path if your dev machine runs a 32-bit operating system. The namespace name is "ASCOM.DriverAccess", not "DriverAccess" so that's another possible hang-up.
I suspect you'll need more help, this isn't the friendliest wrapper. Be sure to find fellow programmers in the dedicated Yahoo group, you are much more likely to get a quick response than here at SO.