there is no such thing as equipment too advanced.
I respectfully disagree. While I do agree/believe that anyone can ride any snowboard equipment, what's affected is the efficiency of progression (and in some cases the ride itself). An advanced board where it's stiffer will serve well to those who know how to control the board and their skills bombing down the mountain. While it will most likely cause a beginner to catch edges left and right (especially if they're not proficient at linking turns and ride at slower speeds). In retrospect a beginner board is more forgiving. Same with bindings (IMO). A stiffer binding that will transfer power and quick initiation to the board edges will be good for more advanced riders, however could have a negative affect to new riders.
Again, I believe anyone can ride any gear, however it's the progression that will suffer for the beginners. If a newbie uses gear tailored to their skills, I think they'll progress faster than using gear made for more advanced riders. Unfortunately, 80-90% of beginners just want the best piece of equipment. This can be attributed to the mentality of having the latest and greatest and in many cases the "bling factor". More often than not, this equipment is reserved more for those that are skilled.
I remember when I first started riding, I wanted the latest and greatest best out there. I went out and bought a Burton Custom at that time. I used it the first 3-4 times out and was progressing somewhat. A buddy of mine suggested I use a more beginner friendly board. Unfortunately I can't remember which board it was back then, but do remember it made a significant difference in my learning. I was able to pick up snowboarding faster and progressed much quicker. I ended up borrowing his board for the next couple months and by the end of the season I was doing much much better on my Custom.
OK sorry for digressing...back to the OP..what is your style of riding? That will help in determining the type of bindings best for you. As snowolf said...check your stance width and forward lean of the binding. One fun part of learning is experimenting with your gear. I would exhaust all options before dropping cash in another set of bindings.
The Ride SPI's aren't a bad binding. I have the Ride Delta's paired to an Atomic Axum and they're great. They're very responsive when you need them to be and the right flex for freestyle type riding.
I also have Rome Targas paired to a Rome Anthem board. They're very stiff and transfer power and heel/toe initiation very well to the edges. While they'll serve a more advanced rider better...I know many who are beginner/near-intermediates that use them and like them.
Best of luck in your decision. Again before "possibly" wasting money...try exhausting all options to see if it corrects your problem.