hmmm I can't reproduce that error ! Are you able to load the image file in lite-c ? If you're able to load it in lite-c, could you post or send me an example project or the part of the script were you call it ?

get the C# wrapper:
for A7.85.4 and A8.30.4, Version 2.3.9
at http://acknexwrapper2.matthias-auer.net/ or visit the thread