So close. ;)
Your code is trying to access a variable/parameter named Project::MaxRowsPerPull
In fact, the $ is significant so you need to reference $Project::MaxRowsPerPull
Also note that you have the data type for the parameter as Int32 but are then pushing it into Int64. You can always put a smaller type into a larger container but if you tried to fill the parameter with too large a value your package will asplode.