This is just a wonderful dessert.
The reason you use pretzels (or bugles) is because you want the salty/sweet contrast. Graham crackers or cookie crumbs won't give you the same effect.
Completely cool the pretzel crust after it is baked.
Spread on the cream cheese layer and refrigerate so it gets as firm as it can. Be sure to spread it all the way to the edges so it touches the pan all around. Otherwise, your Jello may seep down under the crust and make it soggy.
Add the frozen strawberries (with juice) to the hot dissolved Jello and stir until the berries and juice completely melt and keep stirring until the Jello thickens and has consistency of raw egg white. Then pour it over the cream layer. It won't seep under the crust. It won't melt the cream layer and it will jell all that much faster. You will have success every time and it is luscious!