Thanks for the answer. But we are using Labview 6.1,on win2000 OS and the Application builder installs a whole group of files in the c:\program files\National Instrument directory, with Shared and Datasocket subdirectories where you can find the lvrt.dll in c:\program files\National Instrument\Shared\LabVIEW Run-Time\6.0 directory. Also, The application builder doesn't seem to be installing any lvrte.dll file.
(NOTE: I'm using the installation of the labview runtime with the application builder in order to see what are the files and registries that are modified/added and then try to replicate that without the application builder, but it seems a bit complicated, there's a whole hierarchy of files installed and many registries modified/added)