UseDLL fails to load dll

[agshah]

Hi,

I have IS 2022 InstallScript MSI project. 

In install script setup.rul I try to use UseDLL but it fails to load the dll.  The dll does not have any dependencies.
I also tried with a dll that does have dependencies and they are all in the same folder.
As seen below, I even hard-coded the path and dll name in UseDLL directly to rule out any issues.
I also added c:\testfolder to the system level path env variable to make sure there are no loading issues.
Kindly help.

nResult = UseDLL ("C:\\testfolder\\test.dll");

if (nResult = 0) then
MessageBox ("UseDLL successful \n\n.dll file loaded.", INFORMATION);
else
MessageBox ("UseDLL failed.\n\nCouldn't load .dll file.", INFORMATION);
//abort;
endif;

thanks.