Troubleshoot LoadRunner Vugen Errors Loading Custom DLL's

Issue: While using the lr_load_dll function, the user receives the following error:

"Action1.c(x): Error -19890 : C-interpreter run time error:
Action1.c(x): Error -- File error : LoadLibrary(c:\temp\MyDll.dll) failed : The specified module could not be found."

The error above can occur if the compiler fails to locate or load the DLL. You can check the return code of lr_load_dll to verify if this is the case.

Example code:

//---begin code---//

int x;
x = lr_load_dll("MyDLL.dll");
lr_message("return code = %d", x);

//----end code---//

If the function above returns 11, that means LoadRunner failed to find the file.

Check the following:

1. Double check the directory, and make sure that the DLL is in the correct path as specified in lr_load_dll function.
2. Make sure that all the required files are present and available to the DLL.
3. You can use the Windows Dependency Walker (http://www.dependencywalker.com/) to check if any dependent DLL's are not available.
4. Is the DLL a 16-bit DLL? If so, it is not supported.

If you are loading the DLL from the script's directory, make sure that the DLL is listed in the Controller's Design View -> Details -> More -> Files.

If you are still having problems, try to put your DLL into a path that is specified in the PATH environment variable of the machine. Modify the reference to the DLL if needed.