Couple of thing to try.

Make sure any nexus or max_entity commands are before the load_level command.

Run the level with max_entities set to 1000 and tank-tracks disabled.
If it runs clean, re-enable the tracks and put in a text-panel showing
a counter of how many are active. [xxx = proc_status(Tack_Track_Action)]
Just to tr and see what entities are going nuts.

What is probably happening, everything runs smooth, then one function somewhere
goes nuts, creating hundreds of entities (during the same frame)until the engine crashes
so your debug-entity counter doesnt get updated with the actual count.