What is it you want to do? LabVIEW can access dlls created in LabVIEW and in any other language like VC++ or CVI (C for Virtual Instruments--it is NI's C compiler). LabVIEW can also create dlls for other languages provided you have the application builder. It should be very clear which of the articles in the second link you should follow.
If you want to access a dll in LabVIEW, there is a shipping document entitled "Using External Code in LabVIEW". In LabVIEW 6.1, goto help >> search the LabVIEW bookshelf >> Using external code in LabVIEW.
Jeremy