Simulation of Linde nitrogen liquefier on DWSim.

The Linde cycle is a simple thermodynamic process for producing liquid air. To minimise the complexity of the process further, I have taken nitrogen in place of air. The process has only a few components, a mixer, a compressor, a simple counter flow heat exchanger, a valve and a phase separator. There are two loops, requiring two recycle blocks.

Please help me with the following questions:

1. I am attaching a DWSim file. The recycle blocks have been connected properly. Once it is started, the calculation does not stop; the information panel keeps moving, showing "Script Data updated Successfully" about five times a second.
2. The buttons "Solve Flowsheet (F5)" and "Abort Solver (Pause/Break)", apparently are doing nothing. Nothing visible happens on pressing them. Same is true for F7.
3. All the lines in the diagram are in blue indicating proper solution except for the streams connecting to the recycle icons. Pressing the "Debug object" command returns "error - function not implemented". Data in different streams show erratic results.
4. I shall be grateful if the flow sheet can be made to work.
5. DWSim is a sequential modular simulator. The software decides the sequence in which the different modules will be executed. Is there a command through which we can know before the execution starts in what order the different equipment blocks will be executed?
6. Is there a way of single-stepping the simulation, i.e. doing only one block at a time and seeing how the results have changed by that one step, and where it actually breaks down.
7. How do I stop the simulation process midway? I pressed "Abort Solver (Pause / Break)"; nothing happened; the information panel refused to stop.