Thanks for using NextGEN Gallery Optimizer!
I believe the reason your slideshow isn't playing is because you appear to have the NextGEN option "Show first" set to "Slideshow" at Gallery --> Options --> Gallery. This isn't an often used feature, so is not currently supported in Optimizer...however it is scheduled for inclusion in the very next release of Optimizer Premium.
If you're already using the Premium version, please send me an email and I'll forward you through the preliminary release. This feature is already coded-up and ready to go.
Hope this helps!