Solution
Since a DLL is an executable that other applications can use, you need to install the LabVIEW Run-Time Engine on your client computer for the LabVIEW-built DLL to work. Whether the VIs and functions are built into an executable or into a DLL, they require the appropriate Run-Time engine to work.
The version of the Run-Time Engine that is installed on the client computer should be the same as the version of LabVIEW in which the DLL was developed. You can also include the Run-Time Engine as part of your application if you create an installer for the DLL. This option is available in LabVIEW 6.0 and later. For more information on how to include the Run-Time Engine with the executable, refer to
How Can I Include Additional Installers with My LabVIEW Applications' Installer? .