There is nothing in principle stopping you from building a 2.4 kernel for Puppy 2.01.
In practice, there are some issues with UnionFS under 2.4 kernels, and Puppy 2.01 depends heavily on UnionFS.
Would running your app under Puppy 109CE or GrafPup 1.04 be an option? They both use 2.4 kernels.
This topic has just come up in the official forum linked at http://www.puppyos.com
by the way, you can find more discussion there.