Support is a free service which may or may not be provided. I do not have enough information to determine the cause.
I disagree with you when I pay $50 for professional edition. If I pay money for your software then I fully expect a full support for one FULL year. If it is FREE then that kind of attitude make sense because who can complain when it is FREE?? Got it?
Also, I don't understand why you feel that you don't have enough information? Maybe it is because you are NOT asking any more question to help you determine what is wrong?? I have gave you the answer that there is NO error in forum error log so now that mean the next thing you need to do is figure out or maybe ask for access to my site so you can find out.
Otherwise, I will gladly give your SMF Gallery Pro a negative comment free of charge.