Semicolon (C:\) is missed (typical error when developers hard coded a system path???)
I just copied FreeImage.dll from location where installed plug-ins for XnView or GIMP. Is it OK?
I browse to directory C:\Users\??UserName??\.gimp-2.8\plug-ins where your plug-in for Gimp supposed to be installed. I found out file riot.exe. From curiosity I double clicked and got message - libgimp-2.0-0.dll is not exists. I checked a directory where Gimp has been installed and found out that this dll exits (directory C:\Program Files\GIMP 2\bin). The problem is that your application x86 and try to look for a x86 path but I installed x64 version of GIMP (one more hard-coded path???)