Solution
If the definitions of the functions, which are listed as 'not found', do actually exist in the header file, they are not recognized probably because of the usage of complex structs datatypes in the prototypes of the functions.
Generally in this situation, you would have to manually create the wrappers for these functions using
Call Library Function Nodes .VI. Go through the
Tutorial: Configuring the Call Library Function Node to call a Simple DLL and reference the
Configuring the Call Library Function Node (LabVIEW Help) documentation for information on how to do this.
If you need access to functions which are not implemented in the header file, you would have to contact the provider of the DLL library to determine the prototype of the functions.